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rzkas's picture

I live in washington state,Grays harbour county. Planing to build a house with a rectangular four corners plan . Lot is flat/leveled. I have desire for slab and crawlspace type of foundation. I heard about hybrid foundation.  (a founadtion where some part is slab and the other is crawlspace) The house is 32 feet depth. I want to divide/split the house foundation into two. The rear 16 feet crawlspace and the front 16 feet slab. All my plumbing fixture are at the  rear of the house. Frost line is 18inches.  is it possible to build a hybrid foundation. Share your ideas about this type of foundation and with  Washington state climate.

One would have to ask (post #215412, reply #1 of 7)

One would have to ask "Why?".  It's needless complication.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

instead of doing slab all (post #215412, reply #2 of 7)

instead of doing slab all over with plumbing buried.  you can have the plumbing and hvac in the crawlspace area for future maintenace and remodel.  overall it less expensive to build  the foundation and subfloor and it gives an  easier front entry with front concret porch.  

Sure you can do what you are (post #215412, reply #4 of 7)

Sure you can do what you are proposing with 2 different foundation types, but like Dan, I agree with "why?"  I know you answered him, but I don't think cost would be a good reason.  Both parts of the foundation will require the same depth footings so why not make the whole thing crawlspace?  That crawlspace will need a rat slab poured, so whether crawl and slab, or just crawl, you will be using almost the same amount of concrete in either scenario.  The only viable reason I can think of for doing what you propose would be the desire for a polished radiant concrete slab as a finished floor.  

I answered your other thread (post #215412, reply #3 of 7)

I answered your other thread in general discussion. Why do you have it in two places?


Essentially, this hybred foundation is done all the time. Any house with an attached garage, with slab, is a hybred foundation. So what is your particular concern?

i posted and i realised i did (post #215412, reply #5 of 7)

i posted and i realised i did it on the wrong topic.    in our area when the crawlspace is built no slab on soil.  the footing for the crawlspac with stem wall and the soil will be cover by black  barrier.   no concret.   since the crawlspace has it stem wall in the middle/center of the house. the front of the house will need slab prep which require mild excavation and a 6" slad is poured.   planing to have a concret porch.  will only need half crawlspace subfloor framing and house walls go up. 

If you aren't going to pour a (post #215412, reply #6 of 7)

If you aren't going to pour a floor in the crawl space then you have even less reason to go with a slab at all....that foundation wall down the middle is the same as it would be if it were on the far outside so now the only concrete work you are adding is the 1/2 foundation walls on each end and you are subtracting out the entire slab.  Yes you will have to frame the entire floor rather than half but you save on not pouring half a floor.  If you ever want hardwood on the concrete its a much bigger pain in the butt than it would be if you had a framed floor.


But I suspect that you have already made your mind up that you want to do things as you have stated and only came here seeking validation not true will reject anything that doesn't fit within the construct of what you already have stuck in your head.

not  quiet.   i like a (post #215412, reply #7 of 7)

not  quiet settled  on a decission.   i like a crawlspace and slab foundation.  instead making a choice i heard of a hybrid foundatin that gives you both.    as for flooring the they have new viynl plank or bamboo that can snaplock and install on slab .  my concerns are how it will react in the long run. everything new functions great. but as it age it function deminish.  


the crawlspace excavation will be the 40 feet width x 16 inches depth with stem wall around the perimeter.  the slab will also have it own footing. on it perimeter but will share the middle stem wall and foot. that stem wall and footing is what separate the slab from the crawlspace.