Concern About OSB Flooring Quality in New Build

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spupazza

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Hi all,

I'm in the process of buying a new build and recently had a walk-through of the property. I noticed that the flooring on the first floor is made of OSB boards. However, the boards look quite rough—there are deep bumps and they’re far from smooth (I am not sure yet if there are uneven surfaces).

Is this standard practice for builders? I was expecting a more finished subfloor, especially in a brand-new home. I’m wondering whether this is something I should raise with the builder and ask to have replaced or properly leveled before proceeding.

For context, I have the letter of offer from my bank, but we haven’t done the drawdown yet—so I still have some leverage, I suppose.

Would love to hear from anyone who’s dealt with similar issues. In attachment there are a few pictures of the OBS boards on the first floor.
Thank you.
 

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i think OSB subfloor like that is pretty standard, are you planning on putting wood or carpet over it? if its carpet get the fitters or DIY to make sure those OSB boards are properly secured down if not they will break your heart with creaking etc
 
Thank you @Blackrock1. I'm planning to install SPC planks over the OBS boards. When you say that the OBS boards need to be properly secure down, what do you mean exactly? Do the OBS boards in the attached pictures look not secure?
 
spupazza said:
When you say that the OBS boards need to be properly secure down, what do you mean exactly?
Click to expand...
walk on then and see what you think, they are probably nailed down with a nail gun, that wont be enough to hold them with movement, they need to be screwed into the joists really in multiple places.

builder probably wont do it for you so itll need to be the floor installer.
 
That is a bit rough but standard.

Like Blackrock1 said above I can't see enough fixings. Probably the absolute minimum nailed down. You'll have to to get someone to go around and put loads of extra screws in to screw the OSB to the timber floor joists. Not Nails! This will help prevent creaking floors in 2-3 years time when everything has fully dried out and settled down. Its not a snag or defect so the builder doesn't have to do it.
 
That looks dog rough and damp? in places.

I thought OBS fibres were to run at right angles to each other to provide stability, strength, and a level platform for the top floor covering. Those floors look anything but. You may have challenges ahead.
 
What's SPC, is that a floating or glued down thing like LVT? Just asking as that wouldn't be smooth enough for glue down imo
 
I thought so, I put down vinyl tile myself in a few rooms, all were stuck down type both glue and self adhesive. One was on a plywood floor but it was a lot better than that one and I screwed it down all over the place! If floating I'd imagine it will be fine as think there is an underlay with that.
 
Wasn't a new build but before laying wooden floors on our creaky upstairs we lifted the osb board and added cross supports between joices. Then glued a 10 mm rubber strip on each joice before replacing the osb. Never had a creak since.
 
By the looks of it that boarding in your house was left outside exposed to rain and sun , the glue in it has degraded and some of the strands are all lifting . You need to get that seen to . How did your engineer not spot that ? I presume your drawing down stage payments ?? I would not be happy with that finish .
 
CorkHome2022 said:
How did your engineer not spot that ?
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It's cosmetic. Structurally it's still fine. Nobody is going to fall through that floor. I'd have no issue signing that off and inspect buildings and construction sites regularly. It's not a floor finish so doesn't have to be aesthetically pleasing which is the issue people here are having with the photos.

If the OP wants they can lay 6mm ply on top of this OSB. You could glue and screw it down (after you've screwed the OSB to the joists) and that will give you a nice new clean surface.

EDIT:
Another option that's rock solid it to lay 6mm tile backer board for the bathrooms and ensuites. You put down adhesive, then the tile board and use screws to push it down until the adhesive sets. Perfect substrate to tile onto then.
 
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thank you guys for sharing your opinion. @Duddaa I'm going to install SPC tiles and SPC walls panel in the bathroom, not tiles. If I install the SPC tiles which have integrated underlay, do you think I can install them directly on the OBS board, or would be a better choice to screw down 6mm of ply on top of the OBS?
@CorkHome2022 I'm going with my engineer this Friday as ask him what he thinks what the OBS board.
 
Yes you can install the SPC onto the OSB.

Now personally I'd like a second layer of defence. The chances of something with the SPC in a shower area are low but if something happens, I wouldn't want a leak down into my sitting room or kitchen below. Therefore I'd put either 6mm ply or a 6mm tile backer board over the OSB and on top of that paint on a waterproof shower tanking kit. Its like thick rubbery paint. It's belt and braces. All can be DIY too. You don't have to pay someone as its relatively straight forward.
 
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