Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 8/15/2016

Hwat is the best flooring to put over a slab foundation.

We now have cheap pargo flooring in the living room and hall, carpeting covers 3 bedrooms, all on a slab foundation. We want to remove the carpeting and cover the living room, hall, and bedrooms with the same type of flooring. What is the best, good quality flooring to use on a slab foundation, ~900 sq ft. We are thinking, bambo, cork, wood, or good pargo. Help please.

Do you have the same question? Follow this Question

1 Answer


You can find a number of previous similar questions about basement/slab foundation moisture issues, vapor barrier, flooring types, flooding recovery possibilities, etc in the Home > Flooring and some (especially about moisture issues and how to reduce the moisture at/under your slab) in the Home > Basement Waterproofing categories of Browse Projects, at lower left.

Basically, in basements ALWAYS use a vapor barrier except with mortared-down tile and stone or glued-down flooring, and a good idea in slab-on-grade situations as well because ground moisture diffuses and wicks up to the the bottom of the slab, then comes through as water vapor (if not as actual seepage), so having a vapor barrier under that is fully airtight sealed to the wall plates (or better yet under them in new/remodel construction) is a cheap protection.

To see if your slab is subject to moisture issues you can do a simple test, though season differences exist, with about 6 foot square sheet plastic taped down for a couple of days then lifted to see if there is visible condensation on the plastic or darker color to the concrete - test both at center and around perimeter.

1) If totally dry after the test and not subject to period of extended ground wetting (like a true rainy season) unless you have full exterior vapor barrier on the foundation, then I would still use a vapor barrier under any lay-down (as opposed to grouted-down tile or stone or glued-down sheet products), but pretty much any sort of flooring could be used.

2) If only fairly dry (may have a some condensation but not full coverage or discoloration of concrete), then a BREATHABLE padding and carpet (open weave, not tight or solid-backed or foam) can be used, tile or stone, sheet vinyl usually is OK, solid vinyl strip flooring like Pergo. Any other type of unglued lay-down flooring will usually be OK if put over a vapor barrier - though the nail holes from nail-down hardwood flooring makes that a pretty iffy proposition.

3) if pretty damp after the test and concrete turns dark, and/or you have seasonal periods where the slab looks dark or where you know the water table capillary zone (the dark colored damp zone 1-6 feet above the water table) reaches the bottom of the slab, you have known mold issues in the area, or your slab has underdrainage with a sump pump operating to keep it dry, I recommend against any sort of organic (wood or fiber) flooring. Tile and stone usually OK with portland cement based mortar and grout; or 100% vinyl strip or vinyl sheet flooring or a very breathable synthetic fiber (nap and backing both) carpet over a vapor barrier. But hardwood/laminate/carpet even over a vapor barrier are iffy because of the risk of mold, and if subject to flooding from seepage into the basement definitely assume those will be trashed in that event.

4) Also, if subject to flooding due to high water levels or possible power failure causing sump pump not keeping water level down under slab, basically only lay-down area rugs or carpets (not nail-strip held carpet) which can be quickly removed and cleaned, and 100% unbacked, unpadded vinyl strip flooring (Pergo and Armstong and others) with snap connections which is removeable can be expected to survive being removed and cleaned before it goes moldy. And of course grouted down tile and stone usually fare well, but occasionally start popping up in those conditions - especially if long-duration wetting or many cycles of it.

BTW - obviously if you live in a rainy or very humid area the plant fiber based materials are more prone to problems, whereas in dry desert or arid area soil less of a concern, though ground mosture evaporating to the air from the groundwater will still accumulate under a slab and result in some vapor transmission through it to the overlying flooring - so unless the flooring is more permeable than the concrete, or you have an effective vapor barrier (which in damp slab conditions can sill mold underneath it), you can still get issues - particularly in homes kept quite cool by air conditioning as that promotes condensation at the concrete surface, whereas warmer home temps (unless high indoor humidity) can evaporate a lot of moisture and avoid mildew/mold as long as there are air exchanges in the room.

Oh - less common treatments which do extremely well in damp conditions - polished or stained concrete, or to a good but not flawless extent concrete with polyurea floor coating over it. Epoxy commonly good but sometimes no; floor "paints" basically fail in actually damp or wet concrete situations like 3) or 4) above. On rubber/vinyl removeable lay-down "tiles" - definitely need a vapor barrier under them if used, because they act as a vapor barrier to moisture movement so will commonly support mold on the underside if used on bare concrete slabs.

On your specific materials -

a) bamboo to me is a poor joke and a ripoff - have seen so many new installs ripped out by either owner who had it put in or by new buyers, because of mold, splitting, dirt impregnation. Whoever thought of using grass as a flooring product (unless laid down loose and thrown out every week or so) was a fool in my opinion.

b) Cork is moisture susceptible and will mold easily, so consider equivalent to organic fiber carpet discussed above. Also has issues with crumbling and dinging from usage wear.

c) Laminate/engineered wood made with wood fails more readily from moisture than thick hardwood flooring, but hardward can have more moisture-induced warping problems.

d) Vinyl laminate same problem unless 100% vinyl through its thickness.

e) Linoleum will mold in damp conditions - commonly OK in condition 2) above but can have problems - and you have the issue with sheet products in conditions 3) or 4) of choosing between gluing down (which means no vapor barrier is possible and may mold) or loose lay with vapor barrier underneath, which results in scuffing damage from furnishings and waves and creases leading to cracking over time.

f) From among the choices you gave, any should work in conditions 1) and maybe 2) but to be on safe side if you have a choice I would go with vapor barrier under a loose-laid laminate or strip vinyl product. Hopefully with slab on grade not subject to condition 4), so with condition 3) I would go with vapor barrier under a pure vinyl product as my first choice, though an unnailed snap-joint wood might be OK if vapor barrier is well sealed at base of walls and any penetrations like air duct registers.

One other recommendation - if going with an engineered wood/laminate or vinyl product make sure it has a substantial "wear layer" thickness - some of the products these days, especially box store products, have a very thin veneer or "decor" layer (as thin as 0.2mm) with no clear wear layer over them so wear through fast, so make sure it has a thick "wear" layer - a very thick clean vinyl overcoat to protect it. Or if refinishable laminate with true wood veneer decor layer, make sure to get one decent wear rated - with thick enough decor layer for as many sanding and refinishes as you think you might do (zero under about 1-1.5 mm, about 1 mm more per sanding above that) and a multi-coat polyurethane or better wear coat. Saw one new engineered wood floor recently where the owner rubbed clear through the laminate decor (wood) layer just using baking soda to clean up a stain - could not have even been thin paper thickness, and had just evidently a single coat of urethane or varnish on it - effectively no wear coat. And remember - you can get a heavy residential/light commericall wear rated flooring material for maybe 25-30% more for materials (no difference in installation cost) so total maybe 10-15% more expensive for a much longer-lasting product.

Answered 3 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy