Slab Homes

[sputnut]

Are homes built on slabs there the same moisture / mold problem they are here in Illinois? Seems to me they would have to be, but I see a lot of them. It seems to me the homes on at least 2 foot stilts would be much better. True?

comin' your way soon!

[kalakoa]

Slab construction has a long-term health impact that goes beyond the mold issue: every step you take is a little harder on your joints because the slab does not "give" like a wood floor. It gets really bad once you're 50-60 years old.

Best local use of slab that I've seen: a house built on "stilts" over a slab -- the "downstairs" was a little short (for me) but with awesome storage and easy access to the wiring/plumbing, house "upstairs" was tall enough to catch the breeze.

[Rob Tucker]

kalakoa is correct. The human body was not built to walk on concrete... bad for the joints. That being siad I don't think there is anything about concrete that encourages mold. Concrete and cement is alkaline. Alkaline inhibits mold. Concrete has no organic content, hence no food for molds to grow. Wood products are preferred environments for mold. The paper on drywall, for example, is cellulose (wood fiber) and cellulose if food for mold. Just add humidity.

There are very good alternatives to using wood products. Wall board is available without paper facings. Steel framing, cementicious sidings, foam and plastics..... it is available and economic to abandon wood as a building material.

As a master carpenter I came to the conclusion, some years ago, that wood is the worst investment for a home... especially in Hawaii.

[Carey]

Yes & NO...lived in a house that was 1/2 on slab growing up in IL (solid clay soil) & now have a slab home here....The ground here is much, much, much more permeable than our IL clay soil homeland, so the water is wicked from the slab (my growing up home always had mustiness in the slab rooms & basement with concrete foundations) AS LONG AS YOU ARE ON A LOT THAT DRAINS... (had to add that, as there are some more swampy lots here)

OK, we are in that magic "bad" age...So far, so good (8years on the slab) The last house we had for a 1/4 century was an IL. 1 story ranch with a walkout basement....all oak floors - SOLID red & white oak- never wanted to redo those!... We always walked sans shoes on those floors ...as is the custom here.... we are covering our slab with porcelain tiles, though for the years before we bought it had carpet & that cushy roll flooring.... those floor coverings DID have problems -Can not stress enough how I do not think carpet is right for this side & the underside of the roll flooring showed that it did not breathe the water vapor...

LOOOVE the porcelain, but we spent time finding a tile that was not slick when wet (throwing water on tile samples in the store & then trying to slip on them was fun...esp. the sales staff faces...) had pretty much the colors of local dirt in the pattern....as I knew white would be a cleaning DISASTER here... (my feeling for the tile floors may also be swayed by the sea critters that appear within them ;~) Big plus is that the color & durability mean that I do not MIND shoes on the floor....

We also are not using wallboard in our main house, instead used smooth hardipanel cement board...(many reasons for that, but the main one was due to our aluminum framing) & the ohana was redone with the greenboard wallboard....did look at the fiberglass wallboard, but it was very heavy, itchy & not quite as smooth.... We have not found it totally practical to completely eliminate wood, but are being very stingy with putting it in the remodel...and really do try to make it bug/mold/mildew repellant...

[Rob Tucker]

I have to guess that mainland concrete slabs with moisture problems were not built with moisture barriers. Barriers are commonly required by the more recent codes.

[Carey]

they did & do... older concrete foundations often had hot tar, now more likely poly. However a puka in the vapor barrier makes it a vapor suggestion (heck, even the best barrier will not work as well around the normal foundation holes for plumbing & such....)

Also the heavy clays in many older glacial/alluvial soils do have a habit of working over concrete foundations...and will often expand to non-covered edges, & even crack foundation walls...

[gogould]

I like the slab on grade for a ground cap poured around concrete pilings that hold the concrete first floor up off the slab a good eight feet or more. Kind of post and beams with reinforced concrete
and then fill in with wood if desired up there. Keep the bottom area open and airy. Or just build with wood on the concrete platform up there in the air.
I like the idea of wood on the concrete floors up in the house a nice springy feeling wood.

[sputnut]

BTW... How do those houses on tall stilts deal with the occasional 6.7 on the old richter scale?

comin' your way soon!

[rainyjim]

Houses built on post & pier foundations rather than a poured slab are more stable during earthquakes. I believe the term used is they go 'walking' when the earthquake hits, i.e. they can move more without threatening the structural integrity than a concrete slab can move. That, at least, is my limited understanding illustrated with laymans terms.

[Rob Tucker]

Keep telling yourself that if it makes you feel better.