Tech Talk: Complex Subfloor Repair

“What is the most complex subfloor repair you’ve had to address?”

Ruben Caicedo
Brazilian Floors LLC

It was in a building where the floor was over sleepers. They didn’t have any moisture retarder in between the joists and the floor below, it only had sawdust or an old type of insulation underneath. It was so compacted that it was coming out in little pieces like dirt, and we had to make sure that we encapsulated that area for the repair. Then we had to even it out because the joists were coming down. We had to sister the joists up in order to get a flat surface. That was the only moment we could install the wood across the joists. We had to use really long lengths of the reclaimed wood and it took us forever to acquire that wood. Cutting the pieces and end matching was a tedious part of the job in order to make it look good and be stable.

Willie Short
Coastal Inspection Services LLC

In an older house, the new owners wanted to rip up the tile and install pine flooring. We ripped up that and there actually were two layers of tile with a thick layer of a mud bed. We removed all of that and realized the reason why they have the mud bed there is because the slab was so unlevel. It was the worst one ever. We had to rip all of that up, do some leveling on that, then we went ahead and pinned out a double subfloor because it had to be even with the existing floor’s elevation.

Gary Zak
All Brite Floors Inc.

In the Gulf Coast regions, we have pier and beam homes that have no subfloor. These are houses that are 60, 70, or 80 years old and they have a failure and want to replace the floor. When the house was built, they just put the floor right over the joists and the end joints always rested randomly over a joist without a subfloor underneath. Now that they’ve conditioned the house and you have a big difference between the inside and outside elements, this causes a much greater moisture imbalance from outside to inside. You have to put a subfloor in or use the old floor as a subfloor and put another floor on top of it and install a moisture control system underneath such as closed cell foam to keep the moisture from penetrating from beneath.

The other challenging part of subfloor repair is if you have humps over joists you may have to remove the subfloor and plane down the joists to get the subfloor flat enough to accept a wood floor with the NWFA guideline specifications.

A final thought on subfloor challenges is the importance of educating your customer that we do not make our slabs level, we make our slabs smooth or flat. An old house could be out of level five inches which could result in trying to raise one end of the room up by five inches which could cause collateral issues with baseboards, cabinets, etc.

Leave a Reply

Your email address will not be published.