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HopefulHomemake r
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# Posted: 5 May 2012 03:48pm
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So, the husband and I are putting in our pre-built Amish "cabin" this fall or next spring. We have a very limited budget, so will be doing whatever work needs to be done on our own. We have no experienced help, and neither one of us has done something like this before. I'm also pregnant, so I can't do any heavy lifting, and anything we do will take a little extra time. Anyway, our big project is to put in the foundation, the installation of the cabin itself will be handled by the people making it.
We're thinking of doing a "Coyote Cottage" style foundation - gravel pits dug beneath the frost line, tamped down (by hand), with what I guess are called "deck blocks" on top. The cabin will be somewhere between 20x20 and 24x26, with an additional deck that will be the width of the house and probably six feet deep. So, are deck blocks acceptable for this size of structure, as long as the gravel pits are well below the frost line? Is this going to be too big of a project for two constructions newbs to do alone? Will it hold up over time, or will we need to somehow replace it down the road? Is there a better option we haven't considered?
We have no electricity, the building site is down a narrow gravel lane and up a grass hill, so getting a concrete truck in there isn't really an option, and we might or might not be able to afford to rent something to dig the holes. It's likely we'll be doing this all by hand. Any advice?
Feel free to talk to me at the 5-year-old level and show pictures. I make no claims to having a vast knowledge of home construction. I once built a birdhouse with my grandpa...that's about it.
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trollbridge
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# Posted: 5 May 2012 04:54pm
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Hi Hopeful!
I'm sure plenty of help will come your way as far as the construction questions you asked...........I'm DUH about that but I wanted to congratulate you on your pregnancy and wish you the best of luck fulfilling your dream of having a cabin!!!
Sounds like great times are ahead for you and your husband! Enjoy the anticipation!
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HopefulHomemaker
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# Posted: 5 May 2012 04:58pm
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Thank you. 
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VTweekender
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# Posted: 5 May 2012 06:34pm - Edited by: VTweekender
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Hopefull, to be honest I can't see how just filling the below frost line holes with gravel and putting blocks on top would really accomplish the intentions for the holes...as I can vision that gravel freezing and being lifted from frost.. ....if you are going to dig you may as well set 4x6 foundation grade treated piers in the holes either on top a bag of quickcrete (just toss it in the hole as the moisture from the soil will harden it - punch a few holes) or on a good sized flat rock.....the intention of going below the frost line (about 4 ft) is so the frost doesn't lift and move the cabin up or down in spots, if the base of the foundation you are creating is below the frost line then the frost is taken out of the picture....if you are going to go with deck block then may as well just put down 8" of stone packed down as a pad the size of the cabin and set it on that ...as the structure will be on treated skids I am sure....if you get a little movement you can always jack it and shim it back to level occasionally with thin patio blocks or something..
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Swamphunter
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# Posted: 5 May 2012 06:57pm
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If you are intent on digging the holes, I agree with VTweekender, why not fill with concrete and let moisture do the work? Is it harder to get gravel there or concrete? My opinion for my cabin is Id say to make it easy and do a floating gravel pad. Remove the soft sod, put down driveway fabric, and then add 8-10" of compacted stone. Build of cinder blocks and 6x6 PT girders.
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HopefulHomemaker
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# Posted: 5 May 2012 09:46pm
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The biggest problem with gravel or concrete is that we'd have to get it, or whatever other building materials we use, to the site in the back of our ancient RAV4. Also, because we don't have a lot of construction experience, I'm not sure setting posts into concrete is a good choice for us. What if we don't get everything level, and it dries like that? The deck blocks seem a lot more forgiving of mistakes, as far as I can tell.
With a gravel pad, could we dig down and have the pad sunken, so it would be level with the surrounding land? By just piling it up I'd be afraid it would just wash out. Also, with the underside of the house touching the pad, won't that eventually rot out the bottom of the cabin, even with the decent drainage that gravel provides?
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Swamphunter
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# Posted: 5 May 2012 10:40pm
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Setting posts is more about getting them plumb as opposed to level. They are cut level AFTER the concrete sets by the use of a transit, or a line level or whatever choice you decide.
As far as sinking the gravel pad level, you would be basically creating a pool without good drainage. You WANT the gravel higher than the surrounding ground so you get drainage away from your framing members. You can build directly off PRESSURE TREATED skids that way, or use the skids as girders and build off of leveled blocks. That gives you more air circulation, accessibility to the bottom of cabin and less likely animal inhabited. Anything touching the ground or within 16" or 18" (I believe) of the ground must be PRESSURE TREATED lumber of some sort for the longest life. Remember, PRESSURE TREATED posts that are sunk directly in the ground provide decades of sturdy use as long as there is good drainage.
Maybe some of the more experienced builders can chime in... I only only have intermediate experience....
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HopefulHomemaker
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# Posted: 5 May 2012 10:46pm
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What about framing in the gravel pad? I definitely don't want the house sitting in water, but I can't imagine a gravel pad sitting for years without just crumbling away at the sides? I found a description of a properly made pad:
"To properly prepare a gravel or stone base, will require an excavation of approximately 4-5" of top soil. The size of your foundation pad should be approximately 2' larger than your building footprint to allow for proper drainage. If your building measures 10x16 your foundation pad should measure 12x18. Alternatively, if you intend to have landscape beds with mulch your pad does not have to be larger than the building footprint as this will suffice to catch water runoff from roof. While not required, we suggest a solid and secure perimeter frame to hold the stone in place. Options for the perimeter fram include pressure treated timber (4x4, or 4x6) secured in place with 3' rebar; wet or dry laid Belgian block, granite, brick or paver. The purpose of the frame is to hold the 3/4" stone in place. It also makes for a more finished landscape appearance. The excavation of your pad should be 4-5" with a 1" layer of sand applied to the base. The 3/4" stone should be flush to the top of the perimeter frame. The top of the foundation can be dressed with a finer 3/8" stone or millings/stone dust if desired. Rake and tamp down the stone as you fill until it is evenly distributed and the site is level and flat. Crushed stone provides an ideal drainage for rain or snow melt around the perimeter of the building, especially if gutters will not be installed (not required). Water that splashes directly on the ground will eventualluy create a muddy area that will splash up onto the building walls unless covered with mulch or stone. Finally, make sure the grade of surrounding area does not pitch or drain into your building foundation. Depending on the grade of your property your foundation pad may or may not require installation of a retaining wall."
That's from URL. So they advise either framing it in with wood, or adding some sort of retaining wall. That seems like a good idea to me. If it isn't a good idea, can you explain why not?
Price was an attractive feature of the deck blocks, too. I have no idea how much that many tons of gravel and sand (and lumber, and a power tamper to get the stone compacted properly) will cost. Obviously we will do whatever is going to be best in the long run, within reason, but I'm hoping not to shell out a good chunk of our budget right away.
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Swamphunter
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# Posted: 5 May 2012 10:59pm
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I agree that framing in with PT wood and rebar would be a great idea. For the minimal cost of the material compared to the overall cost of the cabin AND the piece of mind you'll have afterwards in your case, it seems it would be worth the investment. Your cabin is about the same size as ours and we are in the same stage of starting. I am having my road construction done as soon as the rain lets up in NY, and dries a bit. They are doing my gravel pad at that time also. I will be putting pictures up too...
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Swamphunter
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# Posted: 5 May 2012 11:19pm - Edited by: Swamphunter
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I found these pics to make a visualization. From two different sites, but Id DEFINITELY add the driveway fabric under the stone. The first pic is a different foundation, but I wanted to add it. These are for a smaller building, but the idea is the same
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HopefulHomemaker
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# Posted: 5 May 2012 11:38pm
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Two questions:
Is the driveway fabric water permiable? I'd be worried that it would cause rain to pool under the house.
The second picture isn't quite big enough to tell, but do you have those beams sitting directly on the gravel pad, or are they balanced on the wooden frame around the gravel? The third photo makes it look (based on the shadows) like it's balanced on the square frame around the pad. Wouldn't it be more stable if it were right on the gravel all the way across?
Thanks so much for all the help, everyone! You all have me nearly convinced to do the gravel pad, cost be damned.
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Swamphunter
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# Posted: 6 May 2012 12:00am
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The driveway fabric holds the water down, so which would also tend to hold the water up... yes. Hence why I am going above grade, having a good overhang on my eaves, and keeping the pad the same size as the exterior of the building and incorporating a french drain out the back of the pad. The driveway fabric DOES however prevent gravel from pushing down into the ground with settling.
Those pics above are not my structure... just googled images. I believe in the second picture, the beams are just level with the wooden frame. The gravel pad is built up high enough they only appear to be on top though...
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Swamphunter
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# Posted: 6 May 2012 12:01am
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You could always go this route though too... Im not sure how good it would be, still subjected to frost and not as much room for drainage from the gravel. Perk test your soil first
http://coyotecottage.com/cabin/cabinconstruction/foundation.htm
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HopefulHomemaker
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# Posted: 6 May 2012 12:14am
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The source I linked above advised having the pad overhang the structure by two feet on every side. That would catch water, if the driveway fabric were underneath to cause pooling. We do plan to install gutters (for water collection) but that might not happen right away, so drainage in a concern. I see that the driveway fabric would help with settling, but wouldn't a densely packed sand layer under the gravel do the same thing, but also allow water drainage?
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Swamphunter
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# Posted: 6 May 2012 12:26am
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I've seen other websites state that when using framing and rebar around the gravel, the "two feet" extra sizing is not necessary. Whether or not thats accurate, Im not sure.
Im also not sure about the densely packed layer of sand. Good luck to you with your project and keep us posted with pics!! Its very exciting and I spend hours researching online!
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VTweekender
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# Posted: 6 May 2012 01:38am - Edited by: VTweekender
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Hopefull, those pics show that the 2 skids you see are directly on the gravel bed, the wood you see under those are leveling shims....your structure will come with the skids already built onto your cabin, so you would set it right onto your gravel pad.....also if you look closely at the pics you see that the entire pad is about 4 to 8" above grade ...that is done so water does not pool under the structure ...water will run away because the pad is higher than grade, if you use the treated lumber on the perameter or not do make it entirely above grade.....DO make it a foot or 2 bigger than the cabin all the way around, water coming off the building will erode the soil away at the edge of your cabin if you don't....with this extra foot or 2 the water coming off the cabin will find its way downhill away from the cabin as you are about 8" above grade with the stone pad....if your site is on higher ground where your cabin will be then I wouldn't worry about the fabric to much....the water won't build up underneath the pad.....a 10 to 15 yard load of 3/4" stone should do the trick...about $300 or so...
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Swamphunter
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# Posted: 6 May 2012 02:56am
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What he ^ said....
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Sustainusfarm
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# Posted: 6 May 2012 10:30am
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Just got done reading this thread...I think from what I have gathered you all think that driveway fabric is plastic or something?? If it is the same stuff I use, basically a heavier grade landscape fabric, it does not collect water. The only purpose of the fabric is to keep the stone/gravel seperate from the soil beneath. Water freely drains through the stone, through the fabric and into the soil beneath. You need the fabric to keep the stone seperate from the soil or the stone eventually gets mixed with the soil and will not be free draining.
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HopefulHomemaker
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# Posted: 6 May 2012 11:48am
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You're right, I did think that it was plastic. It looks like plastic in the picture above.
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Swamphunter
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# Posted: 6 May 2012 03:55pm
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I did not think it was plastic, but I was under the impression it held the water down to make driveways more solid. Thank you
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trollbridge
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# Posted: 6 May 2012 04:07pm
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It is exactly like landscape fabric on steroids!!! LOL!!! We used it on our bridge approaches and creek bed before the stone went down and it has held up beautifully.
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HopefulHomemaker
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# Posted: 6 May 2012 06:50pm
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So you've pretty much convinced us to try the gravel pad. It's a little more than we were thinking to pay, we we've found a couple of corners we can cut on finishing to make it possible. We're going to put in a french drain on one side, just to make it a little drier. We'll be on top of a hill, so all together I think that'll work pretty well.
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Swamphunter
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# Posted: 6 May 2012 08:28pm
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Take lots of pics for us!!!
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HopefulHomemaker
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# Posted: 6 May 2012 11:38pm
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Will do. We should be putting the pad in (and maybe ordering the house) when we head up in June.
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MtnDon
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# Posted: 7 May 2012 02:38pm
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It is my firm belief that once a building gets to 400 sq ft and beyond they are too big for "deck" blocks. Jan, who built Coyote Cottage got lucky, IMO and had soil that drained pretty good on it's own. His current home that he built himself, is larger and sits on a conventional insulated concrete slab.
Buildings that sit on deck blocks have zero uplift resistance as well.
That said, what does the builder of the cabin recommend as the minimum foundation they want to see in order to offer/honor any warranty they provide with the building?
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HopefulHomemaker
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# Posted: 7 May 2012 08:16pm
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They haven't said. having researched the same type of prebuilt "shed" online, almost all builders recommend a well packed gravel pad. Some say a concrete slab is better, and I'm sure it is, but that's way outside our budget.
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MtnDon
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# Posted: 7 May 2012 09:51pm
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A slab is for sure better. Next best is a concrete or block perimeter foundation. Then 6x6 or larger PT wood piers set deep enough to be below frost level.
There are many folks who have built on gravel pads using deck blocks. Most of them will never admit to having any problems. And none of them ever seem to worry about uplift. I do, but then maybe that's because I have recorded a 63 mph wind speed on our mountain ridge; right from the open side against the north wall.
If you build on deck blocks and gravel you may not have any heave issues if all the moisture can drain away. If the moisture can not be guaranteed to drain away there is no guarantee that freezing will not cause frost heave.
If frost heave occurs a block or two will move upwards. It may or may not settle back. If it moves it is common to have doors bind, maybe windows too. If you don't use the cabin in the freezing weather you may never actually see any problems. Who knows? If you do build on deck blocks and gravel at least also install anchors like those used for mobile homes.
Have you checked with the county or township, whatever the local level body is that would be governing what any applicable zoning laws would require? How about any permitting requirements? These vary from onerous to lackadaisical all across the country. In many places the killer is the disposal of human waste that gets expensive. Check out all those details if you have not yet done so.
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HopefulHomemaker
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# Posted: 7 May 2012 09:58pm
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Permitting is pretty lax in my area. I haven't checked in about foundation types yet (will be calling on Wednesday) but I know owner built cabins are common. I already asked about using a composting toilet, and the guy said it's fine.
I really wish we could put in real piers, but there's just no way. We can't get a cement truck back there, and don't have hundreds to spend renting a (whatever it's called) to dig holes in the rocky soil. No water source for hand mixing cement, either.
Now Husband is talking about wanting to just build the whole thing ourselves. I just don't know.
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MtnDon
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# Posted: 7 May 2012 10:36pm - Edited by: MtnDon
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Piers can be done without a lot of concrete. IMO, if piers are to be used (and they have deficiencies too) it is better to use foundation grade PT 6x6 timbers than lugging in loads and loads of concrete. Foundation grade PT has a heavier concentration of the preservative. They usually need to be ordered in as the ones in most big box stores are just ground contact, as in laying on the ground, not for deep burial for something as permanent as a foundation.
Dig a hole deep enough to get to just below the frost line. Bell out the bottom to 16x16 ideally. Or dig the hole larger than needed. The size is for the only poured concrete you will need, the footer which ideally would be 16x16x8 inches with an X or a # of rebar in the poured concrete. That is about two 60# bags of Quikrete per footer.
The 6x6 PT pier then is set onto the concrete pad. The hole is refilled with the earth that was removed. Add little by little and pound well. A digging bar is almost essential for digging and tamping the dirt back in place. link to a digging bar
The piers are then cut to a level height after they are all installed.
No matter what the frost depth is the 6x6 PT piers should be at least 48 inches in the ground in order to obtain any decent resistance to lateral movement. Height above ground should be kept below 18 inches; if more above ground height is needed I'd recommend no less that 2 more in the ground for every 1 more above ground.
And piers of any kind are not going to work well if the soil has high clay content and/or gets waterlogged frequently or for long periods seasonally.
Let me add that I believe tossing a bag of concrete mix in the bottom of the hole makes for poor low strength concrete. There is no guarantee that sufficient water will be drawn from the soil to make the concrete as strong as it could be. And pouring water in on top of the dry mix is not that great either. There are few short cuts in construction that result in a quality result.
Let me also add that building something the size of a 20 wide or larger may be more than a neophyte builder should do the first time. How about building something like a 10 or 12 foot wide x 14 to 16 foot long building that could be used to hone skills. It could be used as a bunkhouse while building something larger and as a shed or guesthouse later.
The plan should be to get the building dried in as fast as possible. You don't really want to begin and not be able to keep the weather out before the next winter sets in. This does not mean the windows all need to be in, just the floor, wall sheathing on the exterior plus a door and a roof.
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HopefulHomemaker
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# Posted: 7 May 2012 11:11pm
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We have a child already and another on the way, so we can't really do the temporary build thing. When we move up there, we move up there, and something needs to be in place. I'm now working on convincing him to stick with the gravel pad and prebuilt, and it seems to be working. I agree that building ourselves might be out of our league. I just want a house, without spending months on labor.
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