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Slipform Questions from Readers of Living Homes
with replies by Thomas J. Elpel

Questions:

• Where can I find free rocks for building with?
• Will round rocks work for slipform stone masonry?
• Is slipform stone masonry approved by building codes?
• How can we support the second floor if we are doing two stories in stone?
• How can I reduce the cost of the beadboard panels?
• How should the holes be spaced to anchor beadboard panels to the concrete?
• How should I build the window frames in a slipform wall?
• Can we slipform a veneer of stone against our house upon an angle bracket?
• What can you tell me about traditional Irish stone masonry?
• Is there a way to get that "wet-look" to bring out the colors in the stones?
• Is it feasible to build a three-tiered tower with slipform stone masonry?
• Would it be affordable to build a stone castle?

Questions Policy: To avoid re-writing my book Living Homes for every person that comes along, please read the book before you write to me. Then, if you have any questions beyond what is presented in the text, then yes, please do write and ask away! I may be a little slow to answer, since I have more than a few distractions, but I will get back to you in time, and I will answer your question to the best of my abilities. Please let me know if I can post your letter and first name to the website. Thanks!

Also, if you have a better answer to a question than I do, or additional useful information, then please send me a note through our E-mail Contact Page, and I'll add your commentary to the web page. Questions and answers on these pages will help guide revisions of future editions of Living Homes.

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Where can I find free rocks for building with?

This question was not in a letter, but it has come up a few times. There are many places you can find free rocks. Farms are always a good choice, where farmer's have removed them from their fields and stacked them in convenient piles. Just ask, and you will mostly likely be given permission.

Another source is public lands, especially here in the west where there are millions of acres of public lands. The Bureau of Land Management (BLM) has a casual-use policy: You do not need any kind of permit, as long as you are collecting rocks by hand (no heavy equipment) for personal, non-commercial use only. In other words, you can collect all you want for building your own home, fireplace, retaining walls, etc. Just stay on the roads with your truck and don't do any kind of excavation work. There are exceptions for special rocks like petrified wood or obsidian, and there are areas of special designation where collecting would be prohibited, but otherwise the rocks are free for the collecting. Inquire at your local office for issues of special concern.

You will need a permit to collect rocks on Forest Service lands, but the permit is free and you can collect up to five tons per year, and get a new permit the following year. A ton of rocks is approximately one pickup load about a foot deep. (That is a lot of weight; you don't want any more than that in the back of the truck.) The restrictions are similar to those on BLM lands--all work must be done by hand, without heavy equipment, and be sure to keep your vehicle on designated roads. Again, check in at a local office for restrictions on specific areas or types of rocks.

On state-owned lands here in Montana you need to obtain a rock picking permit from a local DNRC field office (Department of Natural Resources and Conservation) for collecting any rocks. State lands in Montana are managed for the benefit of the public school system. A rock-picking permit costs "about $10 a ton". You can pick as much rock as you want, as long as you pay the $10/ton fee. Again, you must be picking rocks by hand, and you must have legal access. Using heavy equipment requires a performance bond for reclamation.

The majority of the rocks we used to build our house came off of county right-of-ways. Basically, a primitive dirt road going into the mountains through a mix of private, state, and federal lands is often a county road, at least around here. You can consult local maps for guidance. The county owns a 60 foot right away, measured as 30 feet each direction from the center of the road. Local laws will vary, but here in Madison County, Montana, the rocks are considered a nuisance. The county has no rock policy, but they are definitely glad to be rid of them. While building our house, Renee and I often joked that we should send the county a bill for all the rocks we picked out of the roads...

Will round rocks work for slipform stone masonry?

Dear Thomas,
I have been actively reading you book now for the last few days and getting very excited about putting slipform construction into practice. I have recently cleared a building lot for my cottage on a 300 acre wooded island in Honey Harbour on Georgian Bay.

As an experienced builder and a "child" of the seventies I have always taken on any project with a sense of commitment to environment, alternative techniques, and a more holistic approach to the end result.

I came upon your book in a rather humorous fashion. Many years ago in my first personal building project I spied a box of books in my rural landfill. These books were a general selection of great material all purchased from the whole earth catalogue, also in the box. One of the books was "Build your own home" by Ken Kern. That book has fascinated me for about fifteen years now, in particular the reference to Flagg and especially the use of the Magdiel form and rubble wall construction. From that knowledge I happened to be surfing looking for Magdiel info and came upon your book.

I am building a log home and was originally and reluctantly planning on a block foundation. I say reluctantly partly because of the hassles of getting blocks to an island.

I have a small Kubota backhoe on site and I also have plenty of stone! I feel that a slipform basement of stone is the perfect way for a self-built project. I have sand available and with some hunting I should be able to secure enough aggregate. How consistent does the concrete have to be?

The rocks that I have on site are more like the rounder type without a definitive flat face. Should I be concerned about this or does it mean more concrete? I suppose if I really looked around I could hand pick some stones with a flat face. Do you know anything about the Magdiel Form, where I can find any information, or whether I need to bother pursuing that avenue? I must say that I enjoy your book very much and feel that with it and my experience I have enough to go ahead and build. I can't wait untill spring!

Yours Truly, Mark

Mark,
Thanks for writing. The round rocks will be just fine. You may need a stiffer mortar (less water), so that it will not run down the face of the stones in the forms.

I usually keep the mortar back from the face quite a bit, then grout it afterwards, but with the rounder rocks you might push the mortar farther between the joints, then avoid chipping too much of it out. A good technique is to pull the forms off 24 hours after a pour and rake over the joints with the back of a hammer to drag off the concrete lumps, smoothingthe joints. It won't be as smooth as a grouted joint, but it is quite a bit less work and it will effectively hold the rocks in place.

Sincerely,

Thomas J. Elpel

Is slipform stone masonry approved by building codes?

Carrie,
A slipformed stone wall might best be described as a "reinforced concrete wall with stone facing". That is technically what it is, and describing it that way would help to reduce confusion when dealing with building codes.

Sincerely,

Thomas J. Elpel

How can we support the second floor if we are doing two stories in stone?

Mark,
Thanks for writing. Yes, you can imbed treated nailers into the outer wall to attach your header joist and joist hangers to support the second floor. The energy loss through the wood shouldn't be too bad since it would be a relatively small area of the total wall space.

Dani's house is a bit different, since the second floor is supported directly on top of the stone wall. She has a 9-1/4 inch thick stone wall up to the top of the eight foot beadboard panels. The floor takes up about half the width of the stone wall. Then she did a thin veneer of stone up about another three feet on the remaining width of the stone wall.

Sincerely,

Thomas J. Elpel

How can I reduce the cost of the beadboard panels?

Dr. Mr. Elpel,
I'm a little stunned today, because I have been receiveing phone calls with prices for the EPS panels. I'm shocked at the prices I'm getting which so far are $1.80 to 2.21 a square foot, which is $58 to $70 a 4x8' panel. This means that I'm up to close to $20,000 dollars in foam panels alone. I wasn't expecting this, and it leaves me wondering if the product you and Dani Gruber used was something else. Of course in your video, the scrap panels were free, so that wasn't figured into the final price of your workshop. Any information would be appreciated.

Sincerely,

Mark

Mark,
Yes, I know what you mean about sticker shock. The quotes you received are probably on the mark. Just make sure you are getting quotes for OSB board on one side only. The cost of these beadboard panels (www.r-control.com) should approximate the cost of a framed wall with foam insulation sprayed in place. In other words, it will be more expensive than a framed wall insulated with fiberglass, but better quality too. When I look at the process for making these panels it doesn't look like it should be expensive, so I wonder if the cost reflects the patented monopoly on the panels. I also know that our local factory operates at maximum capacity most of the time, so they are keeping quite busy enough without lowering prices. Anyway, if "Necessity is the mother of invention," then perhaps sticker shock is the father.

I can see several possible routes around the cost problem. First, you might explore the possibility of getting free panels off the factory scrap piles. I don't know how close you are to a factory, but it would be worthwhile to investigate, especially near the peak of the building season when the factory is at maximum production. Just go directly around back and see what's there and ask the people near the pile which ones you can take, or more appropriately, which ones you cannot take, since the workers may be saving a few scraps for small factory projects or their own personal building projects.

I think there has been some problems in the past with individuals assembling the scraps into buildings, since the panels are structural, while the scraps are not. But there is no problem using the scraps in a slipform wall, since the stonework is the structural part.

Second, you might look at a more modular approach to construction, to the greatest extend that the codes and building inspector will allow. In other words, build a small structure that looks mostly complete and move into it while you build the rest. Be sure to design the place so that you can easily add on to it. That way you can pay for the new panels as you go, or build in sections as you accumulate scrap panels.

Third, you might evaluate a variety of insulation systems that could be incorporated into different parts of your house plans. For example, our house (built before the beadboard method) is bermed into the hill on the north and east sides, with inexpesive beadboard insulation (no OSB board) placed against the concrete walls and backfilled to hold it in place. The south side of our house has a large greenhouse with lots of windows, so there is essentially no insulation there. The west end of the house (the family room addition shown in Living Homes) has double stone walls with rigidboard insulation sandwiched in the core. We used mostly urethane board, working with salvaged sheets found for free or damaged sheets bought at a reduced price from the lumber yard. We "welded" the joints together and filled all the holes with expanding foam sealant to insulate that end of the house for next to nothing. While none of these examples may work in your situation, the point is simply that we used three different insulation systems for the walls in one house, but you would never notice except by my pointing it out.

In other words, you may need to return to the process of integrated design. Add the element of sticker shock into your criteria at the beginning of the process and design the house with the flexibility for modular step-by-step construction with the possibility of several creative approaches to insulation. That may not be the answer you are hoping for, and I really wish I could give you a magic formula so you could buy the new R-Control panels at 75% off, but that's just the way it is. Let sticker shock become the father of innovation and see what you can come up with.

Sincerely,

Thomas J. Elpel

Hello Mr. Elpel,
I found some things out about polystyrene panels that I thought might be useful to your readers: After getting a 'best price' of $57.00 per panel, I went into a bit of a depression. That price was going to put me too far over my budget, and I started to question whether or not I would be able to go on as planned. In that mood I called Derrick. I had been given his number by one foam place, but had not been able to reach him, and I had in fact given up on him, since I have discovered that in the field of construction, there are people who just don't call you back, and leave you waiting for nothing. Most of us don't mind waiting for something--as long as we know it will come eventually, but waiting on people who may never call you back is very frustrating.

Anyway, I did reach him at last, and he was at home and fortunately, in a 'gabby' mood. I explained my situation and my feeling that my plan might be coming to an end soon. His response was "Mark, these people aren't listening to you, they are trying to sell you structural panels. These panels would be the walls. You just need them to be a straight edge and then to be insulation." He went on to describe the various densities of foam for assorted purposes, and said that I could use what is called '1 pound' foam, which they recycle out of what would otherwise be their scrap.

Check out the stone house built by Mark Rehl!

The bottom line is that I will be buying 130 panels that are 9' x 4' without the OSB for $22.00 ea. This is $71.00 more for the extended length (after you add what it would have been to buy the extra panels instead), but I think it will be worth it not to have to cut 130 1x4 pieces of foam/OSB. The 4x8s will be $19.00 each, plus tax.

I will have to glue the OSB to the panels myself. The company gave me a sample of the product so that I could experiment with the gluing. They are very secretive about their gluing process, and would not advise me as to what type of glue to use, other than to say that petrochemical substances would eat the EPS. I went to the local Home Depot where they steered me to 'Liquid Nails' for foam. I took a tube (caulk-gun style) home and it worked. The drying time was a whole day, even though it said 4 hours on the tube. After about 6 hours, it was still goopy-wet. I set an old glass 'slider-door' on top for weight, and the next day it was solid. I used 7/16" OSB, because it is only 1/16" thinner than 1/2" and that is what the foam manufacturer was using. Also it's less expensive. When I finished gluing the panel, it seemed to want to stand on end, and it was very sturdy. The R value of the panel is 22.9, so with the OSB it is at least 23.

I was concerned about the cost of the glue because I paid $2.14 for the tube, and used a good deal of it on one panel. Since then I have found 'construction adhesive' in the paint area of a "Lowes". I have not been able to try it because I have only the one panel, but I'm hopeful, since it says on the can that it can be used for EPS. If this proves to be a good product, I may try to get it in 5 gallon pails.

The OSB is $6.89 plus tax per 4x8 panel, and I will need more of it for the walls, since I will have to cut the extra 1 foot. This is still expensive, but for me it is at least do-able.

A thousand thanks more,

-Mark

Mark,
Sounds like you found a good solution to the cost problem. Congrats on the thrifty thinking. I do have some minor concerns about the long-term durability of the glue... in other words, is the OSB going to be at risk of peeling away from the beadboard after a number of years? The R-Control panels are glued together in a large press, so there is a lot of weight to firmly press the OSB to the beadboard. Personally, I think you will be fine with your approach, especially since the panels will be locked in place by everything else-such as the interior walls that butt against it, the sheetrock that covers it, and the sheetrock on the ceiling material that butts up against it.

However, for extra insurance, you might think about some ways to permanently tie the OSB through the beadboard to the concrete. For example, if you are using wire ties for the formwork the way it is demonstrated in the video, then you might leave some or all of the wire ties in place. Sheetrock would easily lay right over small diameter wires (like tie wire), or you might look at making a shallow groove in the OSB for thicker wires. I would recommend a medium-sized wire, since tie wire isn't very strong, and could also rust through easily where it enters the concrete. The thicker, stiff wire I showed for doing a concrete pour in the video would be excessive for stonework and wouldn't lay flat, so look for something in between.

Sincerely,

Thomas J. Elpel

How should the holes be spaced to anchor beadboard panels to the concrete?

Mark,
I don't know what the best spacing would be, but I think you have the right idea to predrill the holes in an assembly-line process. It is too easy to forget about it later on. The loss in R-value should be minimal, so I wouldn't worry about that part too much. I might put three holes across the panels horizontally, such that two were about six inches from the edges and the third was in the middle (sixteen inches apart from the others). Vertically, I might do a similar pattern, starting about six inches from the edge and spacing the rest sixteen inches apart. This number of holes might be overkill, but you can be certain the panel won't come off the wall. While you are doing some assembly line work, you might also want to predrill the panels for your form wires to go through.

Sincerely,

Thomas J. Elpel

How should I build the window frames in a slipform wall?

Mark,

For the window framing, we've used 2 x lumber in the past, but I really liked the method we used in the video, where we built the frames out of scrap beadboard panels. In fact, you could recycle the scraps cut out from the window and door openings to make the window and door framing.

The one thing I might do different on a house would be to push the beadboard panels all the way to the outside of the wall and stucco the edge to make a six-inch wide "picture frame" around each window, instead of bringing the stonework all the way in as we did for the workshop in the video. Optionally, the beadboard could be trimmed down to make a more narrow frame.

Sincerely,

Thomas J. Elpel

Can we slipform a veneer of stone against our house upon an angle bracket?

Hi,
I recently purchased your Living Homes book and have found that I agree with nearly all of the things you say. ( I would say all, but I don't agree with anyone that much) My husband (he is much more conventional than I am) and I are planning to build a new house this year. I have managed to talk him into building to last instead of putting a double-wide on a basement.

We are planning to use the foam concrete forms for the basement and walls, he thinks that vinyl siding is the way to go, but I would like to use field stone on the outside of the walls.

My question is this; could we use the slipform method and tie into the existing wall with angle brackets? I think a stone house would look absolutely wonderful, and I don't want to mess with replacing the siding that blows off. Please let me know what you think, and thank you for taking the time to answer.

Karen

Karen,
The foam concrete forms, though pricey, are a really nice way to go, and quite energy efficient. Yes, you can bolt a heavy piece of angle iron to the wall and go up on top of that with a veneer of stonework. You don't need forms for it, just some flat rocks 3 to 4 inches thick, plus some mortar a trowel and a little patience. It is not what I would call real stonework since it is only a veneer attached to the wall. Realistically, the vinyl siding should hold up just as well as the veneer. Not that I would choose vinyl siding for any of my projects, but yes, it is pretty good stuff, and you would be attaching it to a great wall system. Sorry, that probably isn't what you want to hear!

I guess my thought is that when you choose any one element (foam concrete forms and a basement), then it limits your choices for the next element. Hence the vinyl siding might be the better choice than attaching a veneer of stone. In other words, I wouldn't close the door just yet on other approaches besides the foam forms. Try to come at it a bit more holistically, so that you are choosing an entire package, rather than choosing the first step and forcing all subsequent decisions to fit that path. I hope that makes some sense.

If you keep the foam forms, then you might consider a blend of stonework and vinyl. For example, stonework up to the bottom of the first story windows would give the house a nice solid and natural look, while the vinyl the rest of the way up would make the house entirely conventional so that it would fit into any neighborhood.

I hope this helps... please let me know what you come up with.

Sincerely,

Thomas J. Elpel

What can you tell me about traditional Irish stone masonry?

Dear Thomas,
First I would like to thank you regarding your philophy, building knowlege and LOVE of stone masonry.

My sister has given me land in Hillsdale, NY next to her and I would like to build a traditional Irish Stone Cottage/farm house. My nephew Will is to be the Contractor and I will assist (he went to a Traditional Building School/VocTech) as well as a fine crew of young builders he went to school with.

In Ireland my family has a working Sheep farm (400 acres on the ocean in Goleen, County Cork) which is also an old Irish farm compound. Meaning, once upon a time a couple buillt a small stone house and then kept adding other sections/houses that are connected, as well as shelter for livestock and then surrounding or connecting stone walls. I miss living in an Irish stone home where the walls are so thick that you feel like you live in a loaf of bread. Well, enough of my home sickness and on to more practical matters.

Here I am, with land and the luck that my sister and brother in law have 80 acres. Now, I know for a fact that nearly all the folks who built stone homes in Ireland did not have money, contractors or Architects! Talk about limited budget, take a look at what remains of the Scalpeens from The Famine!

I will be invistegating the slipform method but would like to know if you might suggest any books that cover Traditional Irish Stone masonry methods for home building.

I also will hopefully be having my roof Thatched by Patrick McGee(Master Thatcher from Ireland here in the States. A finely thatched roof has a 75 year life span, is not flammable and just the most beautiful roof a person could have. Anyway, thanks for putting up my tome and I hope we can be in contact. I thank you in advance for answering my query.

Warmest Regards, Phoebe

Phoebe,
I would guess that traditional Irish Stone Masonry was simply stacked very carefully, using shims to fill the voids and level the stones. There was probably a crude mortar between the stones, used more to block air flow through the walls than for strength. The strength of the wall would rest entirely in the skill of laying up the stonework. In other words, I don't really know anything about traditional Irish stone masonry, except that if you needed a house and had rocks but no money, that would be the logical way to proceed.

Insulation in any northern climate would be necessary to minimize or eliminate heating costs. One technique you might consider would be to build the house out of insulation panels, as we did for the little workshop we built, then to rock up the outside without forms. The insulation panels would provide backing for the one side of the wall, while serving as a nice straight guide for the rockwork. You would be able to measure off the insulation panels when placing stones to keep the stonework nice and even. The end effect would be more of a brick-layered effect, like the stonework in our fireplace, shown on the bottom of this page.

Notice how the stonework on that page looks different in that project than in the slipformed walls pictured on the same page. It is a stronger way of doing stonework and uses less concrete. You could still include reinforcing bar too. I realized when building our workshop that with the insulation panels for backing, this formless technique might be just as fast as the slipform method we used. I hope to try it out on a small project sometime soon.

Sincerely,

Thomas J. Elpel

Is there a way to get that "wet-look" to bring out the colors in the stones?

Hello,
I was hoping you could answer a question of mine. We had a natural river stone fireplace built in our house. Is there any way to get that "wet-look" in the stones to bring out that colour that is so obvious when wet?

Thanks for your time. Andre

Andre,
I've wondered the same thing. We use an acrylic-based floor sealer on our tile floors, which really brings out the shine, so it seems like it should do the same on stonework. There are many different brand names with different formulas, but all seem to be acrylic-based. (The tile sealer looks like milk when you pour it out then dries clear.) These products are especially intended for porous tiles like terra cotta.

I tried using an acrylic floor finish on some stonework but it turned out disappointingly dull and filmy. So, to better answer your question, I called my local brick, block and tile shop to ask for advice. They suggested the same thing: use an acrylic floor sealer (Brickyards use brand names and may not know whatâs inside the bottle, but they will describe it as a ãwater-based sealer.ä) So that didnât really answer the question. I guess you could try applying some acrylic-based floor finish to a small area of stonework that is not easily visible. I would leave it for a few months to see if it dulls out over time. If it looks shiny and stays shiny, then you could do the whole fireplace.

Otherwise, I am guessing that a polyurethane-based product might be more effective at creating and keeping the wet look. I don't have much firsthand experience with polyurethane, but the woodwork I have seen treated that way seems to stay beautiful forever. So you might look for a clear polyurethane that could be used on stone or masonry. And again, test a small area out-of-sight before committing to doing the whole fireplace that way.

Good Luck!

Sincerely,

Thomas J. Elpel

Is it feasible to build a three-tiered tower with slipform stone masonry?

Dear Thomas,
I have recently purchased your video and book on slipform masonry. I also have acquired some land in the Mount Shasta area, CA. I have dreamt about building a mountain retreat with an old castle style . . . cheaply. Slipform sounds great and the project of a lifetime!

If you have time, a quick question. I am going to (would like to) build a small home, but much like a tower. I am attaching a picture in a word file of what I am thinking about. I will consult an achitect, and an engineer for feasibility but before I do that, I would like to know your opinion . . . can this be done with slipform?

Thank you for your thoughts

-Oliver Davidian

Oliver,
Thanks for writing and sharing a little about your Dream. Unfortunately, there is one serious obstacle to overcome to make this Dream a reality: there doesn't seem to be anything supporting the walls of the upper floors. Even if the roof of the lower levels were poured of concrete and heavily reinforced, you cannot just float the walls of the upper levels out on top of the concrete slab. The weight is immense. The upper walls must be supported all the way to the ground. Of course, the other problem is that if you brought the walls all the way down inside, then there would be no open space left inside the lower levels. Sorry I don't have better news!

Sincerely,

Thomas J. Elpel

Would it be affordable to build a stone castle?

Hi,
I came across your site just after poking through many other useless ones and thought maybe you would be the one to help me. I don't know if there's a word to describe myself, but, I'm not one for the old box style, typical commerical homes with 2x4's and Aluminum siding.. I like big spaces, large rooms and such that I can explore and such. I know I'd never be a millionare so to get a big mansion in the richy part of town would be out of the question. However, I have always wondered if I could take natural materials around me and build my own monstrosty somewhere private..

I've always been partial to medieval history... Castles with towers and drawbridges and such.. I live on the east coast of Newfoundland Canada just outside of St. John's, and if you know what it's like here, you'd know that it's sorta close to Ireland or Scotland; geography wise; with endless Rocky cliffs and such stretching along the coast.

What I want to do is probably outragous.. But, if I could purchase some parcel of land on top of a coastal cliff, could I afford the cost of building a substantually large Stone stucture castle?.. Do these projects get costly. Like into the $500,000 range?

Sorry if this is so vague, I'm writing this at a very late time. I have so many ideas and questions floating around in my head, and I really want to do this project with the least amount of money involved.. I really don't want to hire labours either. I'd rather build on my own, even if it would take the time to study masonery and bricklaying and what ever other course would need to be takin.. And if you know what weather is like here in Newfoundland..

Can you tell me if building a structure like this can really last a long time here?

Cory

Cory,
Sounds ambitious! Our early house plans looked more like a small castle, but it evolved to become much more house-like by the time we started building.

Yes, you can build your own castle, although from your description it sounds like a life-time project. If properly built it would certainly last for centuries and would likely become a famous landmark, "Cory's Castle".

Cost is mostly a function of design. You can make a structure about as cheap or expensive as you want it to be. That is one of the key points in my book Living Homes, designing a building to meet your criteria for cost and energy efficiency.

I hope this helps!

Sincerely,

Thomas J. Elpel