DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Flooring (
-   -   Additional subflooring question (

ElizaWhyza 03-23-2012 06:08 AM

Additional subflooring question
I posted before about my subfloor. We didn't realize it , but our GC based all stair and door heights on our existing 1/2" subfloor which dates to 1979. We have specs from our architect that says we should have 3/4" t&g, but she says it was just boilerplate and intended for new areas with a new footprint. We're remodeling, but not adding sf to the house. She said the GC would not have foreseen that we had 1/2". The grey area comes in because we had an additional 1/2" of plywood everywhere that we previously had carpeting, and it was discarded. We would have been happier to keep that extra 1/2", and didn't know the GC wasn't keeping it.

The hardwood floor contractor had expressed concern about the subfloors, and even suggested possibly removing and then resetting the stair to allow additional subfloor to be installed.

Rather than ripping out the stairs, our architect suggested applying for a variance based on hardship due to unforeseen conditions. If granted, we would then add 1/2" of plywood screwed and glued, and have the bottom step being 1/2" shorter than the other stairs, and the top stair being a 1/2" taller than the others. The GC wasn't too happy with that idea, but he agreed.

The floor guy dropped off a couple of bundles of wood for us to look at, and when at the house, walked around and said the floors weren't really so bad, and we could add "cats" underneath to support the floor in the basement. He said he was concerned about having the stair heights being different.

Given that the flooring guy had been so concerned before, I'm pretty sure that the GC got to him, considering how intense his concern had been. When I next spoke to the GC, he asked me if I had applied for the variance. I said we were considering not doing it, but weren't sure. I asked him about cats, which he said was blocking, and he said that was a great idea. He then added that he was really, really concerned about the differential in those stairs.

Hmmmm..... the phrasing of that comment was almost identical to what the floor guy said. WHAT A COINCIDENCE!!

We have a 2" space between the current subfloor and the bottom of our french doors, and if we add another 1/2" plus the 3/4" hardwood, a rug would be impossible in front of those doors. I think the contractor just doesn't want to do the work of installing the plywood, especially if the doors also would have to be pulled out, the opening reframed, and re-installed. I understand that it's not optimal to have different stair heights, but currently, the new stairs are slightly elevated, waiting for the floor to be installed, and the last step as you go down is at least a 3/4" taller. Upstairs, where the hardwood also is yet to be installed, it's 3/4" shorter. We go up and down quite often and don't even notice it.

We don't especially want to go the route of ripping out all of the existing subfloor, although we know installing 3/4" t&g is the best choice. Our architect has concerns about doing that, since the new subfloor would be detached from the subfloor under the sill plates (but I know it could be blocked underneath).

Bottom line, would sistering and blocking also help to reinforce the subfloor? Our floor joists are 2 X 10's, 16 inches apart. The flooring will run perpendicular to the joists. Given that the stairs are installed, as well as the french doors (two operational and two stationary), is there a way to make the current 1/2" of plywood work by adding reinforcement from below?

If this were your situation, what would you feel ok with as a solution? Thanks for reading!

Daniel Holzman 03-23-2012 07:09 AM

You have a reasonably common, yet complex problem. You have two contractors plus an architect involved. I suggest you sit down in the same room with the architect, the GC, and the flooring contractor and hash out a solution. You already know some of the options, no doubt the architect has some other ideas, probably the GC also. I am puzzled why the idea of sistering came up in the last paragraph of your post, when it was not previously suggested. Is there some concern that the floor is not stiff enough for hardwood?

ElizaWhyza 03-23-2012 07:44 AM

The sistering was my idea. The flooring guys felt there was sponginess in the plywood and suggested improving the subfloor. I was just wondering if a compromise might be sistering as well as adding blocking.

The architect suggests getting a variance and letting the stairs be different at the top and bottom due to adding an extra 1/2" of plywood, but consistent throughout the staircase itself. I don't think she realizes that there wouldn't be any room for a rug in front of the door.

The GC thinks it's fine the way it is, but he is likely motivated by not wanting to reset the french door panels, and also fearful that if the variance isn't granted, he might have to rip out the stairs, AND reset the doors.

The issue surfaced when floor guys came for a last measure, and we saw that one room had an extra 1/2" of plywood, and that it had been removed in the hall. My husband and I assumed the GC was going to replace it in the hall, but then we learned the stairs were set at the lower level. We then would either need to have a transition saddle between the rooms, or have the stair levels be different, and on top of it, there is the issue of whether the plywood is sufficient.

Bob Mariani 03-23-2012 11:05 PM

If you are using 3/4 solid wood you will be fine. This minor movement of your sub floor is not as big of an issue as the safety lost in making a step depth different . Tripping at the top is not good for one's loved ones. Your GC is right!

ElizaWhyza 03-25-2012 07:54 PM

Thanks, Bob for the benefit of your experience. I appreciate the input on the top stair height, and I understand how dangerous & easy it would be to trip on the way up if you weren't anticipating needing to raise your knee and foot higher for the last step. Is the same true of the first-step being a 1/2" shorter? We have the extra 1/2" of plywood in the living room, which is right next to the hall where the stairs are. We could add the 1/2" in the hall, which would make the bottom step 1/2" shorter than all the others, but the top step would not be higher than the others. If we did that, the hall would be at the same level as the living room, and we'd have a more stable floor.

Bob Mariani 03-26-2012 05:35 AM

Bottom step works the same way. We quickly adapt of step to the steps so to say. Meaning that we develop a stride that becomes automatic. A large or smaller step creates a hazard. Maybe you can adjust the other steps slightly to slowly change the height by shimming each step slightly different to gradually adjust the height. You do not want more that a 3/8" variance.

All times are GMT -5. The time now is 04:09 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1