We are building a 19x24 cabin on a cinderblock foundation. At the highest point, the crawlspace will be 4-5 feet depending on how much our budget allows and if one method is cheaper than another. My question is is Quikwall (by Quikrete) suitable and strong enough for a foundation compared to using mortar to lay the cinderblock? I would plan on using rebar vertically throughout and horizontally through at least one course of blocks. Anyone of experience in this and have any tips on using Quikwall? Which is better and/or cheaper?
https://www.thenaturalhome.com/drystackblock.htm
https://www.thenaturalhome.com/surfacebond/quikwall2013.pdf
I like surface-bonding-cement (SBC), whatever the brand. It adds strength, smooth continuous appearance, and a bit of water-flow resistance. And I have tried the "dry stacking" method. But my preference is to use standard cement blocks and conventional mortar-joining ... for me, it is quicker, the layup is more stable during construction, ... and the block dimensions work best using the standard mortar joint. After the mortar joint layup is complete, I come back and cover the whole block wall with a cover of SBC, inside and out. YMMV.
Thanks! But do you think drystacking be sturdy enough? Also a few questions on construction.
Do you use rebar and how far spaced vertically and horizontally?
What are wall ties used for?
Do you need to fill the cavities with cement or would dirt from the site work?
TIA!
Traditional mortar is slightly cheaper. IIRC, there was about a $200-$250 difference for my 20x30.
I also preferred the dimensional accuracy of the blocks. Traditional mortar also helped me fix the slight hump I had from my footing pour.
As far as strength goes traditional mortar is stronger in compression (600 psi vs 400 psi) while SBC is stronger in flex (3x stronger). For code and wood construction both methods are strong enough for design purposes and the building code does not differentiate between them.
Rebar requirements are design specific. A large part that will affect it will be what zone you are building in, and how much unbalanced fill you will have.
Luckily the building code lays this all out in charts free online.
I did a quick post to reading the charts to determine wall thickness or rebar guidelines.
http://countryplans.com/smf/index.php?topic=12374.0
In many applications rebar is not required by code, but not a bad idea. Even when not required, it is not uncommon for #4 rebar to be placed vertically in cores ever 48". You would fill the cavities with grout (a watered down mortar or concrete).
I have never personally seen horizontal rebar used in a masonry foundation for simple home construction. I have seen wire ladders used, but not often on such simple construction.
I tried to be as detailed as possible about the block foundation, because I noticed over the years many people were intimidated to tackle it as a diy project with no experience.
http://countryplans.com/smf/index.php?topic=10998.msg143361#msg143361
Both quikrete and sakrete put out videos on SBC and mortared block walls. Easy to follow.
Wall ties are used to tie a brick face to the concrete wall, which I don't think is applicable to this situation.
Very helpful, thank you:)
They would not allow the drystack for my dads place in MN so I would check with your inspector In my opinion mortar is the only way to go with block I had rebar every 32" and I did a bond beam on the top course with rebar you can either cut the block or buy bond beam block I poured concrete in the corners which was code for me and the cores that had the vertical rebar and filled the top bond beam with concrete all other voids where filled with sand then I used a rubber membrane and primer to waterproof the exterior of the wall.To me putting on surface bonding cement is a waste of money I have a friend that repairs foundations for a living and its almost always adding vertical rebar and filling the cores
How much space is needed under a crawlspace? We are building on a hill so one side will be deeper than the other. We're thinking of just doing the minimum. The county we are in here in Arkansas doesn't have any building codes/inspections so we can pretty much do what we want. So what is best or recommended for crawlspace depth?
I am in the building process right now. My foundation is 3 courses high. That makes for a really tight crawlspace when doing anything under the house. I wish I had made it 4.
I live in the warm, moist Southeast ... and my preference is for a very high crawlspace. A "walk-space" is what I really want...a ventilated sun-lit "almost-basement" but without a finished floor so to avoid addition tax burden.
If you're going to surface bond, dry stacking is better than mortared joints. The mortar actually weakens the connection made by the fiberglass in the SBC... You'd probably have better luck and spend about the same filling cores, and skip the SBC, if you're going to mortar joints.
We dry-stacked, surface bonded and then poured every few cores. In hind sight, we should have poured THEN surface bonded. When the concrete cured in the cores, it moved the walls just the littlest bit, but it was enough to crack the surface bonding.
18" is the code minimum for a crawlspace. 24" is much easier to flip over in. 24" is an even 3 courses of block too.
18" is uncomfortable at best.... personal experience
I prefer mortar and poured cores. Aside from the underfloor space requirement I believe there is an 8" minimum distance between untreated wood and grade outside, siding, etc. When possible I prefer to level the crawlspace, make it ~3'+ and pour a "rat slab" under there, about 2" thick slab to seal things up and make it more pleasant to work underneath. I really hate the kind where I have to decide to go in face up or face down. I came out from under one black and blue but I did prevail over the attack mouse ;D
We see folks say very often that they have no codes/inspections, a little clarification might help. You probably do have codes (codified laws) pertaining to construction. You may not have enforcement of those laws on the local level (inspections).
Would dirt from the site be ok to use in the cores and use cement in the cores with the rebar?
Why use anything?
That's what I'm wondering, do I need to use anything? :D Or do I just need it in the cores where I'm placing rebar?
I don't, we just mix thinner pea gravel concrete for the poured cores. Back in the day we would sometimes fill the other cores with zonolite or pearlite for a little more insulation. Ideally the grouted cores are also your anchor bolt cores and the 1/2" x 12" anchor bolt is tied to the rebar in the poured core... ideally that rebar comes up out of the footing with an L of rebar cast into the footing pour, thus bolting the house to the footing (it can huff and puff but it isn't blowing off of that connection ;D).
I didn't fill the cores ... sort of. I had plenty of stones and rocks fall in in the process of mortaring the blocks. Pay no mind.
I did "top" the blocks. It is when you fill the top block cores. You can use a tight mesh screen in your last mortar row, or just stuff plastic in (old bags, I used old tarp) to hold the mortar in place until it cures. Stuffed newspaper was the old way of doing it, but many pointed out this could be a source of mold, so I switched to plastic. It is helpful in keeping out water and, most important to me, rodents. I had a few entombed into the wall in the process. One less home for them.
http://countryplans.com/smf/index.php?topic=10998.msg147130#msg147130
Don_P uses 12" anchors. I used 10" J bolts. It leaves 7" (code minimum) in the block and 1.5" for the sill plate and 1.5" for the washer and bolt. Don_P uses the best practices. I just didn't want to have to add cores to a second row of block. If you are adding a core and rebar, I think an extra 2" bolt is 50 cents extra. By memory, I believe J bolts have to be every 6 feet.
I filled my cores that where not filled with concrete with sand for the added thermal mass it provides and to support the concrete of the continuous bond beam I hooked my j bolts under the rebar of the bond beam which is tied to the vertical rebar and I placed bolts in every concrete filled core and 18" from the corners I used cheap all star concrete mixed with sand and cement something like 3 bags concrete 5 gallons sand 1 gallon cement I dont think I would want to use organic dirt in the cores