Framing and Sub-Flooring - Minimum safe sub-floor thickness?

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View Full Version : Minimum safe sub-floor thickness?


k19_1234
09-02-09, 09:16 AM
My kitchen contains two areas – cooking and eating.

The cooking area has 3/4’ hardwood floors that are raised 3/4’ higher than the hardwood floors in the eating area. Thus, the subfloor of the cooking area matches flush with the top of the hardwood of the eating area. This creates a terrible and dangerous lip in the floor. I’m in the process of removing the hardwood floors from the cooking area.

The joists underneath are 2x8 spaced 14’ apart. It appears the subfloor is 1 3/16’ thick in the cooking area. From the kitchen it looks like particle board but from the basement it appears to be plywood (I’m still investigating).

I want to apply a laminate in the cooking area. Is this safe to do? Is the 3/4’ hardwood (that I’m removing) needed for structural reasons? What’s the minimum safe subfloor thickness for the cooking area that contains heavy dead loads (fridge, stove, oven, counter, etc)?

The laminate won’t solve the lip problem but it will reduce it. I would ideally like to reduce the thickness of the subfloor but don’t know if it’s safe to do.


HeresJohnny
09-02-09, 09:33 AM
From the kitchen it looks like particle board but from the basement it appears to be plywood (I’m still investigating).

It's likely that you have a plywood subfloor, and the particle board you are seeing up above was an underlayment for vinyl or some other flooring material. If that is the case, there is no reason you cannot remove the particle board underlayment as well. Hopefully, it was not glued to the plywood subfloor. You'll have to find out how thick the plywood subfloor is.

k19_1234
09-02-09, 09:51 AM
It's likely that you have a plywood subfloor, and the particle board you are seeing up above was an underlayment for vinyl or some other flooring material. If that is the case, there is no reason you cannot remove the particle board underlayment as well. Hopefully, it was not glued to the plywood subfloor. You'll have to find out how thick the plywood subfloor is.

I guess the more important question is...if the subfloor of the cooking area is flush with the top of the hardwood floor of the eating area...should I be worried that the subfloor of the eating area isn't thick enough?


marksr
09-02-09, 10:06 AM
Mobile homes use a 5/8" subfloor, I wouldn't want to go any thinner. 3/4" is the norm for sub floors with joists 16" on center.