Proper subfloor preparation is the key to successful flooring installation, but too much can be too expensive
Q.: As an estimator for a major commercial architectural firm, I am thinking it might be a good idea to specify, at least to some extent, self-leveling treatments for concrete slabs, so that it is in the budget from the start on jobs that involve existing slabs. Spurring my concern, is the increasing use of wood- and tile-look vinyl sheet and LVT, both of which seem to require fairly flat floors in order to maintain a realistic aesthetic. What do you recommend and what are the budget figures I should include?
A.: Self- leveling varies greatly based on the size of space and how rough (deep) the self- leveler will be.
It is not necessary to self- level just because you are putting in a vinyl or LVT product. It can often be taken care of with one or two coats of skim coating the floor. This can be done for less than 75 cents a square foot, per coat.
If you want a real wood look, chances are better with LVT than with sheet vinyl. These products will be in the $4-$6-per- square-foot range, material and installation included, depending on product and total square footage.
In most cases where there is no contamination of the slab that has to be cleaned off first, and we are installing LVT, there is only a need for skimming of the surface to prepare for the new flooring. This normally means two coats — a base coat and a finish coat. This can be achieved for about 75 cents per coat, per square foot.
If the slab is in need of some more help, there may be a need for self-leveling. If the slab is level but not smooth, then leveling may be the most efficient way to go about it. For ¼-inch of leveler on a small area, less than 300 SF or so, costs can go as high as $5 per square foot.
As the area increases in size, the cost per square foot will drop. We recently worked on a project that was about 26,000 square feet, and the cost to the end-user to surface-grind, prime and self-level was $102,000, or just less than $4 per square foot.
There are some noticeable differences in the way architects are writing specs lately. For example, at the Veteran’s Administration, they now are asking either for pricing in the base bid to grind, prime and level after abatement, or, as a bid item, the unit cost of the additional floor prep. We also have been seeing a change in the abatement specs, in which the abatement now requires take up of old VAT, and a wet scrape of the old adhesive with no solvents, followed by an encapsulating sealer and full skim of the area.
This method seems to be fairly cost-effective, with the cost of the encapsulation coming in at 75 cents per square foot, and then the skimming added to that. Doing the abatement and encapsulation in this manner does away with the need to grind away the solvents, then prime and level.©
Contact our expert Nick O’Dell at firstname.lastname@example.org