Fitting solid wood floor to chipboard?

[BillyWillySilly]

As part of the renovations of the spare room, I've decided to take up the old pine floor boards and replace with new. We have a solid oak 18mm thick floor to lay which I was going to mechanically attach using hidden screws. I toyed with the idea of directly fixing these to the joists but think better of it. If the flooring was 22mm then I probably would not think twice.

At the moment I just cannot seem to get a timber merchant to deliver and maybe its the case of wrong time but I have had a quote for Egger P5 that is reasonable. A couple of things concern me, primarily if the floor ever has to come up. The boiler is in this room and replacing with floorboards seems more sensible. But also, I read that the hidden screws for oak flooring don't work well with chipboard although this stuff if the Egger P5 with the fancy glue.

Thoughts?

 

[Deleted member 174758]

Plywood flooring (possibly larch/softwood) and a Portanails-type hidden nailer?

 

[oldbutnotdead]

18mm oak should be very very stiff- can't see the point in laying a new floor under the new floor, might as well have left the old boards down. How are you dealing with the 18mm step into the next room? Doors?

 

[Deleted member 174758]

Surely that depends on joist span, spacing and cross section as well?

 

[BillyWillySilly]

18mm oak should be very very stiff- can't see the point in laying a new floor under the new floor, might as well have left the old boards down. How are you dealing with the 18mm step into the next room? Doors?

Ironically there would be a noticeable step if I secured the oak to the joists directly. There's a fair gap under the door - I suspect from some meaty carpets in the past. Joist span varies which is part of my concern - 430 to 450 and directly securing would probably incur some degree of wastage. I have yet to open the oak flooring boxes to ensure they acclimatise.

In terms of a new floor, I have to make repairs and cannot get the same sized boards without seemingly a lot of effort. Plus, there's the opportunity to use the old floorboards I take up to make repairs elsewhere in the house to it makes sense in the longer term. And then the opportunity for a new, level floor to lay the oak down seems to support the idea of a better finish in the end.

I suppose there's just this snobby element to using chipboard. I hated it in our old house but that was mid-80s rubbish that had been cut to high heaven over the years and squeaked like hell. It certainly was not modern Egger/Caber floor. I just spoke to the technical manager dealing with CaberFloor and he said there should be no problem in securing screws to the P5 at all.

 

[oldbutnotdead]

That all makes sense. I'd still be wary of fixing into chipboard, and the higher spec boards you're using won't be much cheaper than 20mm PAR timber boards (t & g would be dearer but you don't need t & g, your oak will cover the gaps & stiffen where needed)
EDIT Timber from a timber merchant, not the DIY sheds

 

[BillyWillySilly]

That all makes sense. I'd still be wary of fixing into chipboard, and the higher spec boards you're using won't be much cheaper than 20mm PAR timber boards (t & g would be dearer but you don't need t & g, your oak will cover the gaps & stiffen where needed)
EDIT Timber from a timber merchant, not the DIY sheds

If only I could bloody get some PAR! Only two local suppliers got back - one has next to no timber at all and recommended the p5, the other would be hugely more expensive. However...this has given me an idea. If I could get them to plane 22mm, it would not matter the widths as I could shiffle the boards around and fit new on one edge only. Maybe they have enough to accommodate?

Fitting completely new 20MM X 145MM PSE works out over £110 more expensive than chip the Egger P5. And the PSE 22mm SAWFALLING REDWOOD is just under £200 more expensive than P5. But if I only need 20m of it then its easier all round. Question then is should i use some fibre underlay to take out some of the unevenness on the old boards or use a glue? Or would the nature of oak floor, securely fitted make up for that. As it's an upstairs room I am concerned a bit about sound proofing.

 

[BillyWillySilly]

Where this all started was exposing an old hearth under the floor boards (I have another thread on here). Now I am left with this:

So now my plan is;

• fix additional timber to the joist that has been cut, removing the rest of those partial boards.
• Cut an inch off the plasterboard allowing me access to the end joist that has been covered (you can see the end of it in the top right of the image)
• Fit a bracing piece to cover the old hearth - not sure how much I can excavate but I want something on the perimeter of the room.

My main concern here is that a bed foot will be on top of this hearth area and I'm not convinced new floor board and the oak will not bow in this area over time. There's no joist at all in the left corner at the edge - maybe fit a noggin directly to the brick work in this section?