Miscellaneous Questions about Stonework

Q: I want to put natural rock on my inside brick fireplace. How do I start? I have different sized rocks, from the quarry, side of the road, etc. I have mortar. But the biggest problem I have is that the existing brick fireplace has a built in three-step to hold up the mantel-how do I get rid of that and start the process?

A: You have picked yourself a tough project. Start with a good stone. Stay away from river rock as entrapped water can pop the rock under high heat. You will want to use molly bolts to attach an expanded metal lath to the brick so your mortar will grab the existing. Your mantel dilemma gets into the professional category. You should be able to chisel out the brick easy enough but cantilevering stone without a thick wall is tricky business.

Q: I love the rock wall you built in your shower. My concern is...how do you clean it and keep it free of mold and mildew? We recently purchased a "fixer upper" and ended up gutting the whole thing because of mold and I don't want that problem to come back.

A: (Kelly) Mold and mildew have not been a problem in our shower. Rocks do not tend to harbor this kind of life. At the base of the shower, where the rocks meet the tile floor, I occasionally notice some mold forming because this place collects organic debris and stays moist for a longer time. This area can be scrubbed clean fairly easily. We live in the arid Southwest, so this might be a factor with molds.

Q: I was wanting to know where I could buy rocks for building? Or to sell rocks. We have a lot of rocks here and I have found no one to sell or buy from. We will be landscaping the front of our house and we have plenty of extras. If you know of any web sites I could go to to buy or sell I would appreciate it very much.

A: (Kelly) Rocks tend to be very heavy and rather inexpensive, since most people don't put too much value on them, unless of course they are gems. For this reason I would expect that the market for rocks would be quite local...not something sold via the internet. I suggest that you check with local landscape supply houses or local landscape designers or contractors for possible markets for your extra rocks.

Q: I live in SC and have dreamed of a small to medium sized ($1400-1800 sq.feet) stone home all of my life.Is this an expensive home to build? Can a stone home be constructed these days for less than $100,00 or even less than $80,000?

A: (Kelly) If you wanted to learn to do the work of a stone mason, such a home could be rather inexpensive to build, since you could do most of the work yourself...but otherwise stonework is hard and time-consuming, and therefore expensive to pay for. I don't see why you couldn't build in that price range, especially if you do some of the work yourself, make a simple design, and carefully shop for materials.

Q: Where does one purchase the stone?

A: (Kelly) The best way to obtain stone is to buy property with stone on it, so you don't have to transport it far nor pay for it otherwise. You can buy stone from landscaping companies, but this could get expensive.

Q: Are there such things as "stone homes built "to go" as with log homes that are advertised?

A: (Kelly) No. The nature of stonework is that it always has some irregularities that do not lend themselves to such kits. Also, stones are very heavy, so transportation costs can be considerable.

Q: I moved many rocks making a path, and now those very rocks will be used to build the structure on top of my hill. So is there some cheaper mortar, special mortar or should I just start experimenting?

A: (Kelly) People have used various methods for building with stone, from dry stacking with carefully cut stones (a lot of work), to using adobe as mortar (tends to erode some over time, but can be quite durable...as with Chaco Canyon), to papercrete (unproven), to standard Portland cement/lime mortar. I would suggest the standard approach because it is fast, extremely durable, and since the amount of mortar used if the stones are carefully fitted is not great.

Q: I will be using thick conduit to build geodesic domes, then mortaring stone up as far as I can go. Now, I had a thought the other day to use stone up half way and then the the upper part to use stucco which would reduce the weight. Now, I know I could build the straight wall Santa Fe style structures, but I want to stay simple and small. Any additional thoughts?

A: (Kelly) Domes are great, for many reasons, and I encourage people to build them. Using a metal geodesic as a frame for doing stonework is an interesting idea, that could work to your advantage. I would suggest using the strongest conduit you can find for the framework. It would theoretically be possible to made an entire dome of stone in this fashion, if you did the stonework in a spiraling fashion and allowed the mortar to set up before adding too much weight in any particular area. Doing something lighter on the upper portion would probably be more practical. I might suggest some form of lightweight concrete for this, because it can also be an insulating material. Also, the triangular sections between the struts of the geodesic can be filled with rigid insulation to provide that needed thermal break. Lots of possibilities.

Q: We are building a home with normal bricks kiln baked, and would like to know how to plaster it using an earth sand mixture. Do you know of a good mix that will not crack?

A: (Kelly) Probably the best way to do this would be to use an ordinary stucco mix of sand and Portland cement, but minimize the lime that is often added, because it is the lime that tends to shrink as it cures. You might need to experiment some with how much lime to use, since it does make the stucco sticky enough to adhere to the bricks. Apply it in a very thin layer. You should dampen the bricks well before applying the plaster.

Q: We have 40 acres of limestone based rocks - are they suitable for building 1) a root cellar 2) a room addition to our existing small cabin 3) rock fence as the one around the 40 acres is in need of repair badly. Thanks P.S. we are on a gradual slope and perhaps some excavation would be possible.

A: Limestone can be soft and absorb water, which would make it less than optimal for a foundation or a root cellar. I think it would be appropriate for a rock fence no matter what. I wouldn't completely count it out for the other uses as some soft stone will harden when exposed to the elements. Your existing fence should show you how it will act. If the stone tends to flake or can be broken by hand then stay away from underground uses. If it holds up to the weather then it should hold up to the construction requirements.

Q: The place where I plan to build is very near some hillsides littered with chunks of limestone rock ranging in size from about four to twelve inches in diameter. What do you think about using gabions to hold these rocks for structural housing wall construction? It seems the wire and rough surfaces would allow easy plastering on both sides, and the spaces between the rock would provide insulation.

A: Boy that's a novel suggestion for a rock wall, but there have got to be some problems with the gabion approach. How thick a wall would you have to build for the gabion to be stable? Will the gabion bulge in the middle? I don't think this type of wall will provide much insulation air spaces or not. I would definitely use the rock for a rubble trench foundation and as an aggregate in your grade beam and build the walls with a more appropriate material.

Q: I am certain you are right -- gabions appear impractical because of the great weights and thicknesses involved. I would really like to make use of all that rock in structural walls. What are your thoughts on slip form walls and their thicknesses ?

A: I have read a couple of books on slip form walls and they seem like a lazy industrialized way to get a rock wall. I am a mortar and trowel guy myself and don't see the point. The R value on a masonry wall is so low as to beg for another solution in most climates. Don't be hypnotized by the availability of rock and forget all other options.

Q: I am considering building a stone house on the Greek island of Zakynthos. The construction needs to be earthquake resistant so cavity walls are out. Please could you advise on the best way of damp proofing and insulating the walls, some of which may be below ground if we end up building on a slope.

A: On a Greek island huh? Do you need an on site consultation? Boy the first thing I would do is get a local guy involved. What affect would a salty sea breeze have on concrete mortar? I would definitely damp proof with wide roof overhangs and not insulate the walls, he says, not knowing the first thing about the local environment. What kind of buildings are on the island? You have got to believe that the old timers have the inside knowledge on what works and what doesn't.

Q: We have put saurtown rock, which is mined here in North Carolina on our exterior walls. We have OSB, then black felt paper (30 lb). Then we attached wire mesh and skim coated it with portland cement. Our rock were then attached and grouted. There is one place on our house that the water pours down the valley of the roof and hits the wall with a lot of water. We have noticed that the inside part of that wall is damp. It is inside a closet. We do not have gutters. Is there something we can seal the rock wall with to make sure the water doesn't soak through the mortar? What can we do to be sure the mortar and rocks are not soaking up moisture and transferring it to in inside?

A: First of all gutters are a must to keep water from pouring on your stone wall. I suspect inadequate roof overhangs. There are any number of clear sealers you can buy and apply to your wall which will help some. If you are getting moisture behind the tar paper then you have more of a problem than water wicking through the mortar. I would suspect water coming in through the top of the wall and seeping down. Just as likely would be water wicking up from an inadequate foundation or through window openings. Look at the seams of the tar paper to see how water gets past this vapor barrier. I am afraid that the band aid of a sealer on your mortared wall will do little to fix your problem.

Q: I was a fresh entrepreneur. I am interested in black stones. Those black stones widely used for foundation purposes in the construction of buildings. (i.e. black stones are laid under the ground to strengthen walls). In rural areas those stones are broken by hands with some traditional tools and accessories. I want to know whether there is equipments that can be implemented non-explosively and economically for breaking of those stones.

A: I have taken some time since receiving your letter to formulate my thoughts on your question. I assure you that I do not take it lightly.
Please consider the possibility that the black stones of which you speak have wisdom that goes beyond our own in certain areas. A rock knows gravity like a human knows love. A rock sees generations of humans come and go like we watch leaves driven by the wind. These black stones have much to say, but a diamond saw or jack hammer cannot hear their song. I suggest to you that the people with hammer and chisel working the stone patiently, in an intimate manner, will slowly but correctly interpret the poetry of a stone. I believe that in mechanizing the process of shaping foundation stone we would separate ourselves from our brother and ignore his wisdom. I make these statements from the fringe of a civilization that has industrialized every aspect of their existence and is paying the price in very real terms. Take the time to listen to the song of a stone and the world will be better for it.

Q: I am trying to make rock veneer for my house. I wanted to know if you knew a good mix for this. I was thinking concrete, vermiculite, sand, and water. Do you have any suggestions?

A: I don't know about vermiculite as an additive to mortar. My understanding is that it is used as a light weight, even somewhat of an insulating aggregate. That shouldn't be of any benefit to you as a mortar when applying a rock veneer. I use a masonry cement for such a purpose, mixed with clean sand, three parts sand and one part masonry cement. If masonry cement is not available to you mix your own with portland cement and lime. Two parts portland, one part lime to nine or ten parts sand. Make sure your water and sand are clean for better adhesion and take care when handling and mixing the lime as it is caustic to the skin and harmful to breath.

Q: I am a landscape contractor in Seattle, WA. My company specializes in ecological hardscape design and natural stone work. Which hardscape product in your opinion is considered more ecological, natural stone or manufactured concrete products? The downside of natural stone is the fact that it is a limited resource that is quarried. On the other hand, natural stone materials last forever and always get reused. I've been debating this with myself for years, perhaps you could shed some light on this subject.

A: (Kelly) I would lean toward natural stone as inherently more ecological to use, particularly if they are found locally and not hauled great distances. Concrete places a nasty load on the environment due to all of the CO2 emitted during its manufacture (about as much as the weight of the cement itself), and then it is usually hauled a fair distance, requiring more fuel and emissions.

Q: I've been interested in building a stone home and have read a fair number of articles on methods. One subject that I haven't found any information on is that of using quarried, processed stone. Specifically, there are a fair number of structures in my area (south of Denver) that were built early in the twentieth century using ryalite from the local quarries. All of this ryalite has been processed in some way so that the builders were able to construct walls using blocks of the same dimension. So my question is basically one of cost/benefit: Is it possible to purchase this type of 'processed' stone today and if so is it sufficiently faster to build with so that savings in labor would offset the cost of the material?

A: I am not familiar with ryalite but have worked with quarried stone in the Colorado Springs area. I was doing historical restoration to the Miramount Castle in Manitou Springs when an elderly gentleman gave me the low down on the greenstone I was working with. He had worked the quarry on the edge of town when he was a boy. The quarry, some of the stone and an old gin pole are still there to be explored though all had been abandoned for decades. He explained that the stone came out of the ground soft and easily worked. As the cut stone was exposed to the elements it hardened and became weather resistant. I have visited three quarries of different stone in the Springs area that were worked around the turn of the century but know of none that are worked now for cut stone. There are a number of different types of stone available to you in that neck of the woods that are quarried with explosives. I have built innumerable garden walls, both mortared and dry stack, out of the granite. The shot rock is definitely the cheapest stone you can buy but you will have a lot of waste and labor. You can also get paletted stone that is easier to build with and with little waste but at great cost. These come in a number of varieties and colors. I am currently building a house in New Mexico out of moss rock that I am collecting myself, an option not available to most.

OK to answer your question, as an experienced mason with little money I would spend more time and build with the shot rock. Paletted stone can cost over $300 per ton vs $40 for the shot rock. There is a reason that you don't see many rock houses being built these days and most of those will have rocks in the yard.

Q: I'm getting ready for the retaining wall job that will be starting in about a week. I now need to select the hand tools to modify the stones I will be working with. I assume that for the most part, I will be removing wobble knobs and such. Would I be just well off with a 3lb pounding hammer and a few chisels? Should the chisels have guards? Is a stone hammer often used? Are their other hand tools I should look at? Do you know of a good supplier to buy these tools.

A: I have a small sledge and a number of chisels I take on any rock job. None of my chisels have guards though there have been times that I wish I had them. I also carry a rubber mallet to help set stones without fear of breaking them. I carry a large tool box full of tools but use my rock hammer almost exclusively in retaining wall work. I've found that a large selection of stones, patience, and my rock hammer for small adjustments get the job done. I can't really say where you may buy a good rock hammer in your area, I got mine at a building supply store, but look for one with a rubber handle. It will save wear and tear on your hands and now and again save you looking for the rubber mallet.

Q: I want to add veneer river rock to my interior wall 15'x8'. Is it an expensive procedure? Would it be too heavy? And what would I use to hold it on there with? I will be doing it myself so I want it done right.

A: You have picked one heck of a project. River rock and veneer don't really go together. The rounded shape of river rock doesn't lend itself to a thin covering. The round rock also leaves you with fairly large gaps to fill with mortar. I usually use an expanded metal lath to mortar to, but your existing wall is an important component and must be strong enough to hold some major weight. You will also need a vapor barrier under the lathing in most situations.  I would first consider if you can find another rock more appropriate for a veneer application. Then investigate if your wall and floor can support the considerable weight of a rock wall. It may be that your rock will weigh a ton or more and the mortar half again as much. A concrete basement wall with a concrete floor can probably support the weight but a framed and sheetrocked wall could crumble under the stress.

Q: I am writing to ask how can I find a Stone Home builder in the State of Florida?

A: Sorry, I have no knowledge of masons in Fla., but I am sure that you can find someone competent by starting in the phone book. I would also go by the supply yards where they sell stone and brick. They will often times post the business cards of local masons. Stone houses are not very common so don't be surprised if you have a hard time locating someone with experience.

Q: I am in search of green home/stone home plans. My husband and I are in our 50's and I want to protect our natural resources, while living very simply. I love plants, trees, animals, and anything that adheres to the standards of protecting our environment. We live in a house that is too big for us and we are eventually planning to retire to western PA, where my elderly parents live. My ideal quest is to build a home that is efficient, symmetrical, and a refuge from the hectic activities of daily living. I am a nurse and would love to extend this nurturing and caring expression into my home!

A: (Kelly) There are a few home plans listed at www.dreamgreenhomes.com that employ the use of some stones, and could utilize even more if carefully redesigned. If you have a source of good local building stones, these could certainly be a good choice for you. Stone work tends to be quite time consuming and requires some skill, so this is not for everyone; also it is not easy to make a stone shell for a house that doesn't leak energy. Often this requires making a double wall with insulation in between the two layers of stones. It may be easier and more appropriate to utilize the stones in certain places on the inside of the house where they can act as thermal mass in a passive solar home.

Q: A friend wants to cover the dry wall in her living room with flagstones (crazy cut). Do you think that flagstones will stick very well? Or is it a good idea to do this? What are the necessary materials needed for the flagstones to be concretely attached to the drywall?

A: You can not attach flagstone to drywall. The thing to do is put that concrete board over the drywall screwed to the studs and the mortar will adhere to that. The concrete board is sold everywhere as a backing to tile etc. Even with the concrete board backing you will have to be careful setting the stone. It can be tricky stacking the rock so go slow and build as solidly as you can.

Q: I just bought a piece of land in the town of Huautla, Oaxaca, Mexico where there are many old buildings made of rock. However, they all have very small windows. Is there a problem to having large windows in a house made out of rock?

A: The problem of large windows on a rock house is that the lintels have to be very strong to bear the weight of all the stone above the window. You can have a larger window if you compensate with a stronger lintel. Steel beams are used in modern rock houses and arched windows have been used historically to support the rock above.

Q: I am replacing the top of two tables inside my home with travertine. What is a good sealer that will protect the top from staining etc. while not a causing a problem with indoor air quality?

A: I have not tried this, but have heard that a water based polyurethane does the job. Try a test spot and let my know how it works.

Q: I want to build a new house out of stone, so what are the different types of building stones and their advantages or disadvantages over bricks?

A: The big advantage of using stone is the local availability of the material. If you do not have a local source of building stone you may be barking up the wrong tree. In most locales I would think that a stone house is a bad choice as it is labor intensive and has poor insulative qualities. Stone is great as a foundation and to retain an earthen bank but 8 foot walls of exposed stone will pass heat through them quickly. Consider using earthen walls or strawbales above a stone foundation.

Q: We have recently purchased a house with stone siding. It's nice to know we won't ever have to paint our house but how do you maintain it. Also, will we be able to hammer into it to hang a window box etc.?

A: I assume by stone siding you mean cultured stone, a manufactured stone looking product put on a stick frame house with a thin set mortar. You will be able to drill through such a siding with a masonry bit to hang a window box but should probably try to find a stud for something that heavy. If you have real stone your best bet is to set a molly bolt in the mortar.

Q: What should we use to drill into a stone on the side of the house for a flagpole?

A: I would try a masonry bit first, hopefully with a rotary hammer drill. Every stone is different though, on some a star drill would work on others you might need a diamond bit.

Q: I want to attach flat rock to my existing wall behind my wood stove. What is the best way and what all will I need to ensure it sticks firmly to the wall?

A: A backing for a wood stove usually requires an airspace behind the stone. Attaching the stone to a flammable wall provides some protection but building codes demand that the stove be a safe distance from the wall. An airspace of an inch or so allows you to put the stove close to the wall. I would start with 5/8" drywall with cement board attached to the front of it and run some lag bolts to the wall with a one inch spacer, I have used metal conduit cut in one inch lengths for the spacer. Leave an opening at the bottom to allow some air flow. Once your board is set up with an airspace behind it lay your rock to the cement board with a type N masonry cement. You may want to add some masonry adhesive to the cement depending on the rock you are using. This is no small task with some structural concerns as the rock can be heavy. Make sure to hit a stud or some other solid member with your lag bolts. I am going off memory but I think you want the backing to be about 18" above the height of the stove if not more.

Q: When laying mortared stone to form the walls of a home, (outside walls), what do you use to secure the rock work to the "skeleton" of the house, in this case, plywood? I know that they use to use metal strips attached to the facing and as the wall progressed upwards, these metal tags were placed between the stone/brick and mortar to help hold the wall in place. Is that what is still being used today? Is there anything better to give the wall more holding strength? My next question is this: When placing lintels in the work for heavy steel window shutters, would it be ok to attach them to the framing of the house and then also stone and mortar them in as well? Or maybe this could lead to rotting of the timber framing, should a leak develop and the lintel would act as a vehicle to carry water straight to the framing? I surely wouldn't want that to happen!! HELP????? What do you recommend?

A: I think most people use an expanded metal lath over tar paper these days. You could sure use brick ties to help out now and again. Make sure you have a good foundation to set the stone on as the lathing won't hold the weight as much as hold the rock and mortar to the wall. This is a tough job for a beginner. Try and get a little experienced help if you can. I doubt the lintels will channel much water to the framing if you have any overhang at all.

Q: Can you tell me if it is better to spend the extra money for a carbide tipped stone chisel/cutter than one without that feature? Seems to me that once carbide becomes dull, and using it on stone could certainly be brutal on it, that re-sharpening it might be a problem???? If I am only planning on building one house and maybe a garage of all stone, which would I be better off with?

A: I have never used a carbide chisel before and generally try and stay away from too much manipulation of the stone. I have a couple of steel chisels and an Estwing brick hammer that get the work done. If it still doesn't fit I get another rock.

Q: I live in Hawaii and have bought a piece of land and I wanted to know if I could build a small house out of lava rock, since there is plenty of lava rock around and I can't afford the lumber prices here. Please tell me how to start building it.

A: Of course you can build a small house out of the lava rock native to your property. Small is the operative word as a rock house can be very time consuming. You will have to pay particular attention to window and door details. I would consider building the house out of rock to the bottom of the windows and then switching to another medium to the ceiling. Straw bales and cob offer inexpensive alternatives that you might actually finish in the next year or two. A stone house, faced on both sides, is a tough project for a beginner to take on. You will sure know a lot about the process by the time you are done but will be building on a novices foundation. Try taking a week or so to build a foundation for a tool or garden shed. Keep going up as long as you are enthused about the process. You will learn a lot and get a feel for what it would take to build a house. There is no way I can write the book that you will have to read to learn a stone mason's ways here in this letter but be assured that you can do this with dedication and a little research and practice. Your first assignment is to learn about the rubble trench foundation and to find out how deep it would have to be in Hawaii. Aloha.

Q: I am a new maintenance director (amateur) for a 110-year-old red sandstone church in Riverside, CA. I need to mount a large bulletin board on the inside of app. 1 ft. thick stone walls with plaster interior finish. I know nothing about such construction methods from so long ago. I am familiar with plaster over wood lath but wonder if that would have been the typical method or if plaster was typically applied directly to the interior side of the (quite rough)stone. Riverside is "earthquake country" and I want the bulletin board securely attached to the wall. Any suggestions?

A: There would be no need to put any lathing to plaster over rock walls. You should be able to drill through the plaster and the sandstone with a masonry bit. Use lead shields or some other type of concrete anchor to bolt the bulletin board to the wall. Make sure that you get into the rock as the plaster won't be as strong.

Q: I want to build a root cellar in the side of a hill in Arkansas. Is it feasible to use local stone? What type foundation and how deep should it be to be functional?

A: I am sure you can build a good root cellar with local stone. You'll want a hard stone that won't degrade if it gets wet. I would try and put the whole structure underground with not much more than the roof above grade. The exact design will be affected by the type of stone, the soil structure and water movement above ground and below. No need for a foundation per se, just start the base course of rock at the bottom of your hole and make it thick at the base and taper it back as you go up. A round structure has a natural strength to it and will enable you to use less rock. I won't try and guess all the particulars of your site and materials but you'll probably have to start the wall out at least a couple of feet thick and keep it 18" thick at the roof line. Water pressure and seepage are concerns on some sites and can be alleviated with a gravel curtain drain around the wall that pipes to daylight. I hope you take on this project. You'll have an enlightening discourse with the rock by the time you are done.

Q: I have a rock fireplace that I would like to use as a waterfall backdrop (exterior) What can I put on this rock and mortar to seal it so that the water fall will not penetrate the mortar or rock.

A: There are many sealers made for mortared rock but I doubt any would stand up to the continuous wear that a waterfall would put on your fireplace. Save your fireplace and put the waterfall someplace else.

Q: I want to build a round house out of stone here in NM. I have no idea where to start or how to do anything. Do you have any ideas where I can find some plans? And what technique would you use?

A (Kelly): I believe that there are plenty of stones to work with in NM; in fact the GHB expert on stone work , Jose' Garcia, is living and working there now. Working with stones can be very hard work indeed, but also very satisfying. One challenge in that climate is providing enough insulation in the shell to make the house comfortable over all of the seasons.This can be done by doing a double wall with the stones, and leaving a space in between them to stuff with insulation, but this of course is twice the work. Another option is to leave the stones visible on the inside, and insulate and then plaster the outside. It is often easier to simply choose certain areas within the house to render with stones, and build the rest of the house with other materials. I have one such roundish plan at my other website: http://dreamgreenhomes.com/plans/sacredmountains.htm  .

C: I was thinking of a double wall sandwiching a layer of pumice/concrete slurry, and then also adding insulation and then plaster to the outside. I really like the octagonal style you linked to below. I'm still figuring out what I want.

Q: I have found a lovely 3 acre lot in the mountains in California. I've been told to just be able to build on it will cost 30 to 40 thousand dollars. The lot backs up to the national forest and is a rectangular shape. There are lots of boulders and rocks. I feel that building a home on this kind of lot can be done for a lot less if I utilize the rocks instead of trying to remove them all. I realize I will have to dig into the mountain and remove a lot of dirt and some of the rocks, but with proper drilling and rebar, I think I still think it can be done. What are your thoughts?

A: I lived in California for a while and the lengths that they go to for site preparation is a crime. I watched as planned developments were razed and compacted and left to sit for years, even decades, till the financial conditions were right to build. If you followed that model I am sure you could spend a fortune destroying the natural setting and developing a flat building site. On the other hand you could rent, or hire a skid loader or backhoe to excavate the footprint of a small house using the surplus dirt for your road and the rock in your foundation. I am doing just that in New Mexico and haven't spent a thousand dollars yet on the house itself. The solar system and cistern have cost a bit but the house itself is built from it's surroundings. Rock, sand, clay soil, and lumber are all offered freely by my momma. There is a lot of work involved to assemble the parts but money is not a prerequisite. Read "Hand Sculpted House" to put you in the mood and build your own dream.

Q: We bought a 72-year old farmhouse. We'd like to redo the cement fireplace sides with river rock. It is currently painted white. Would you suggest FAUX river rock (lighter weight) or the real thing? What mortar should we use, and will it stick to the paint? We thought of drilling little holes and attaching some screen first.

A (Kelly): I would always prefer to see the real thing as opposed to something fake, especially in a house that old. Cement mortar will not stick to paint, but it won't stick very well to the old concrete either, so your idea of attaching some wire mesh onto the existing fireplace is probably wise. A good, cement-rich standard mortar for rockwork should do fine.

Q: I have an uglier than sin cinder block fireplace and would like to rock veneer the exterior. After reading the Q&A on your site, it appears that our abundance of river (round) rock is not the best material. My question is this ... can I take a sledgehammer to this rock and work with the pieces? It seems that this would lighten the load on the wall as well as give me a flat surface to put against the cinder block and also lessen the grout lines between the rock. Feasible ?

A: This seems entirely feasible to me. Some rocks are harder to crack than others, but if you hit them just right they will often break. I have watched masons do this regularly with some very dense stones on a wall at my place in Mexico.

Q: I am currently trying to place my gas firebox into the old wood burning fireplace. I have some kind of rock wall and the firebox cover does not sit flush on it. Is there a way to cut this rock on the wall so I may flush up the firebox to the wall under the rock (kind of inset it a little)?

A: (Kelly) It depends on what kind of stone you want to cut how easy it is. Some stone is rather easily chipped away with a cold chisel. Other stone may require a saw, especially for a very neat job. You can probably rent an appropriate saw at a local rental yard...either with an abrasive disc or even a diamond-tipped blade.

Q: I am building a new house and have collected rocks from the woods surrounding my property. I would like to apply them to the wall surrounding my fireplace. The wall goes all the way to the 8 ft. ceiling and the fireplace is propane gas. I know I will have to put a concrete backer board over the existing drywall because of the moisture from the mortar. Can you please give me some tips on how to do this project.

A: (Kelly) First of all, you should read the directions for the installation of the gas fireplace very carefully so as to comply with any clearance requirements, etc. Beyond this, the stonework is relatively standard, but unless you have some experience with this sort of thing, I suggest that you research techniques for stone masonry (books, etc.), and then try a smaller, perhaps outdoors project to get some further experience. You want the fireplace to look nice, and it takes some skill to do good stonework.

Q: I have seen people use some sort of mesh or wire against the wall also, what is this for?

A: (Kelly) If there is any question about whether the stonework will be sufficiently attached to the wall, then a wire mesh, or periodic tabs that will directly connect the mortar with the wall behind it is a good idea.

Q: I have a concrete pond in my back yard and I want to adhere flat river rock around the wall that is above ground, not the top edge that is horizontal, but the vertical portion. I don't think it's as easy as slapping on some mortar and sticking the rocks on. How can I do this and what supplies do I need?

A: (Kelly) This sounds rather difficult to accomplish, but not impossible. I think that you are right that mortar alone will not likely hold the stones there for very long. So some form of mechanical connection to the wall may be necessary. It would help if there were a solid ledge to set the bottom stones on, but steel might eventually rust out...perhaps reinforced concrete that was securely attached to the wall would work. Another approach might be to drill holes into the wall big enough to insert small rebar rods that would actually support each stone. These rods could be embedded in the mortar and would not be visible.

Q: I am building a new home and would like to use Tennessee field stone on the shower walls and flag stone on the floor. Do you see any potential problems with this?

A: (Kelly) There are many qualities of both field stone and flag stone, so it is hard to advise you regarding this without seeing the material. If the stone seems quite dense and not flaky, then it would probably work fine. For a shower you might want to seal the stone and mortar with a stone or grout sealer to keep it from absorbing too much moisture and potentially molding.

Q: Hello, I am planning on building a smoker out of river rock this summer. The design will be a cold/hot smoker with possibly an independent fireplace in the center. The project will be about 12' long 5' high and about 4'deep. I am planning on placing the entire structure on a 4 inch steel reinforced slab of concrete to assure a long life and to prevent differential settlement. The Firebox for smoking will be on the right at the bottom. There will 2 6" pipes for transfer of smoke, the first will go vertically directly into the hot smoker and the second will go horizontally about 8' to the cold smoker. With this design I would have plenty of room in the middle to build an independent fireplace for recreational fires. My main question is how thick will the walls need to be? And also how much mortar (and what type of mortar) would you place in between the rocks?

A: (Kelly) I don't have any direct experience building a stone fireplace, but my father built one some 60 years ago that is still in use and is holding up just fine. He  used river rocks of various sizes, some of them quite large. I think in general this fireplace is about a foot thick. It is usually best to use as little mortar as possible to set the stones in place. And be care to avoid stones that may have pockets of water embedded in them, as these can explode when heated.

Q: We have a large, cut, slab of red flagstone, 8' X 2'3" X 3". How well could this type of flagstone be used as a kitchen countertop? Are there companies out there that could re-surface it to smooth? Would it need to be sealed?

A: I really can't say much about the properties of your flagstone with the only description of it being red. The red flagstone quarried in Colorado is porous and adsorbent. I have seen it polished and sealed by a countertop company and used for a bathroom vanity top. I doubt that it would be appropriate for a kitchen. I am reasonably sure that it would be a costly endeavor to have it finished and you would still have an inferior product to granite. You might be better off finding a more appropriate use for such a great stone.

Q: I need your advice with regards to building stone steps for access to the patio. The patio door is 6 ft wide and the distance from the patio door to the ground level is 40". According to my calculations minimum five steps would be required. I was planning to build steps 6 ft wide using wall stone (12"x18x"4") as raisers and coping as steps (14"x36"x2") but I'm afraid that the weight of materials might crack the basement wall. Will these steps exert too much pressure on the basement walls? Do you have any other suggestion for steps?

A: The steps you describe shouldn't exert much pressure on the basement wall at all. Certainly no more than any basement wall would be expected to withstand. Most of the pressure will be downward so make sure that you have good compaction below the steps. Now I don't know the specific structure of your basement wall but if you can pile dirt up to the patio doors you should be able to build stone steps with no ill effects.

Q: Recently I bought a one story house, which is complete masonry, made of sandstone. I plan to to completely seal it with exterior masonry sealer. But the problem is that all conventional masonry sealers are rather expensive for me, and I need it a lot , and since I live in Russia most companies won't ship it overseas, due to custom restrictions. I didn't find any masonry sealer in Russian hardware stores at all; seems that people here have no notion about it. Do you have any green recipe for exterior masonry sealer, which could be made at home using commonly available materials? I tried sunflower oil, but it didn't work as well as I expected.

A: (Kelly) If you have the commonly available silicone caulk (clear) you might try mixing some with water and applying it to your stone. I have heard of this being used to seal things from moisture, and it is invisible. You might experiment with different ratios of caulk to water to find what works best... Another possibility is boiled linseed oil, which can be thinned with mineral spirits, but this may leave some coloration and possible residue.

Q: I am moving to Regina New mexico and would like to build a stone home. I read that you have built a home in Northern NM with stone. Where can I get stone? I'm building into a clay/sand slope that I am cutting into. I'd like to make a 2 story home either of stone or a combination of stone 1st floor and metal second. Can I use the stone with mortar for the foundation? How thick should my walls be? I want to gain as much solar gain as possible and my stone home will face south but I need windows. How to build with stone for many south facing windows? I wanted to put a shed style roof on the home with the draining part water snow runoff facing the rear of the home. This part of the house would be somewhat dug into the hill of the slope. Should I change the direction of the roof run off or drainage? Do you hold any workshops in northern NM? Do you have any images of your home available? Would insulating with straw bales be feasible?

A: I am indeed building a home in Mora county. It sounds very similar to what you are planning. I built the foundation out of local sandstone and bermed the house into the hillside so the north wall is solid stone to about 7 feet high with cob above. The second story is timber frame with light clay infill and earth plastered. I am not planning any workshops this summer but would be willing to come to your site and do a consultation. I am sure there are stone sources close to your site as people I know have collected good building stone around Abiquiu.

Q: I live in Ohio on a small lake and have about 75’ of shoreline. The bank is eroding. The lake bottom drops off gradually, so I do not have to deal with any big drop offs near the bank. The bank is only about 6” above the water level when the lake is at its highest point. The level of lake is down slightly but I will still be working in a few inches of water. There is lots of clay in the soil. I have obtained a large quantity of hard limestone rock. My original plan was to dig out enough of the lake bottom to make it flat, stack the rock to make a wall level with the bank and backfill between the rock & bank with the clay/mud from the lake bottom. Now I’m wondering if I should, perhaps dig a few inches deeper and put in a row of partially buried cinder block as a foundation before stacking the rock. If I use cinder blocks, should I drive some rebar a couple feet into the ground to help hold it in place and do I need to fill the cinder block? I wasn’t planning on using concrete. Any suggestion would be greatly appreciated!

A: I don't see how a cinder block foundation to your wall would help. Start your rock wall with the largest stones on the bottom at a depth that that you feel confident that the toe of the wall is secure. Out of the water, I would like to see about a foot of stone below grade. In the lake maybe more. Using mud from the lake bottom to "mortar" the stone would be counterproductive. Dry stack the stone so that the weight of the rock and friction hold the bank. Adding a lake to the demands of a dry stack wall will require some skilled rock laying. Take comfort in the fact that a dry stack stone wall can be repaired easily.

Q: I live in RI and have access to an amazing range of beach stone. I'd like to build a stone fireplace to replace our brick one that is crumbling. The original sits on a very thick cement and rubble pad. My husband is afraid the beach stone will explode from salt water trapped inside heating up. If I gather it from above the tide line it should be ok right? Also what kind of mortar should I use and do I need an inner liner of fire brick?

A: I would worry about using the beach stone. I can't say as I know definitively as to how long a stone has to dry out before you don't have to worry about it exploding but .... I like using fire brick in the actual firebox then you might be able to get away with using the beach stone farther from the heat of the fireplace. Use a type S masonry cement.

Q: We have a home in the South Carolina mountains. We have a floor to ceiling stacked stone fireplace and have recently noticed an odor coming from the rocks. It is not the odor from a fire in the fireplace it is sort of a dampish odor you might notice in a basement. I am worried about mold!

A: (Kelly) Rocks normally don't rot or harbor mold, so the odor is likely coming from something else. Did an animal die in the chimney? Is the roof leaking around the fireplace and allowing moisture to get to other parts of the house?

We just climbed to the attic and noticed damp insulation around the chimney . So it looks like you hit on the problem with the chimney and we will pursue that further.