Old School House in France

[zbc]

I've posted a few times on this on other threads and once or twice quite a while ago in the early days of the project but we are now almost two years in to a project to renovate a school house in our village in France. I thought it might interest a few and I'm sure that you all will be a great source of advice. Originally built in the 1890s, it's in Moselle it hasn't been used as a school for almost 20 years. We started conversations to buy it in 2021 and bought it in 2023. It took about a year to get planning permission and now we are making slow progress to renovate it. It'll be about 200m2 in the end with four bedrooms but sadly no garage yet although space for at least one.

[zbc]

This is what it looks like at the moment upstairs. The reason I started the thread today is that I have my first real question. So far we've had a variety of great builders doing some awesome work at I thought reasonable rates but I've just had a quote for flooring and decorating that seems really crazy. It's a big space and has a lot of high ceilings but 400 Euros a square metre is too much for me so I'll do most of it myself. The one bit I've never done before and seems the most shocking is to put down OSB on this floor to create a level surface for the flooring proper. I looked at OSB and locally it's about 12 Euro/m2 and we have about 100 m2 to do. We've been quoted nearly 20k. Do you think I need to remove the existing flooring before laying the OSB and how hard a job is it to do it myself and get it level?

[Magooagain]

What does the estimate (Devi) actually say?

[foccer]

you dont need level, you just need flat.

When i did the loft conversion on my gaff out there, i just used the thin insulation sheets under the chip board to help with sound deadening.

[smifffymoto2]

Why not lay a lightweight chape?

[zbc]

Magooagain said:

What does the estimate (Devi) actually say?

Dépose de l'ensemble du plancher bois, y compris évacuation des déchet
Fourniture et pose de panneaux OSB22, y compris remise à niveau du support

Speaking to the plasterer on site at the moment he suggests screwing battens to the floor to get a level and laying the OSB ontop

[zbc]

smifffymoto2 said:

Why not lay a lightweight chape?

I'm not really sure. That's the plan downstairs where there is an existing concrete floor, albeit not in great condition but I think upstairs with the wooden floor they want to add some rigidity as well rather than just having a level surface.

[Crumpet]

Looks a shame to cover those nice boards!

I recently battened a floor and then laid board on top. Pretty easy to get it dead flat with a laser level and plastic packers and then fix 22mm chipboard, as long as you can take the height build up. With glued edges and the battens on 300 centres you’d think it was a solid concrete floor.

Why OSB rather than chipboard?

[zbc]

Crumpet said:

Looks a shame to cover those nice boards!

I recently battened a floor and then laid board on top. Pretty easy to get it dead flat with a laser level and plastic packers and then fix 22mm chipboard, as long as you can take the height build up. With glued edges and the battens on 300 centres you d think it was a solid concrete floor.

Why OSB rather than chipboard?

Some of the boards are quite nice but plenty of them are in very poor condition. The roof used to leak a bit and most of the original windows were smashed and rotten. Given more time and expertise I would lift some of the boards and repair one or two areas to keep but even then I'm not sure we'd get something decent.



Battens and gluing and screwing is exactly what was suggested yesterday. I think OSB is preferred for slightly better moisture resistance but also strength. The recommendation was 40mm high battens with 400mm centres and then a thin layer of insulating material between the battens for sound more than heat.

[Crumpet]

Ah that’s a shame but we had the same issue with our original boards being in too rough shape to be able to salvage.

The green moisture resistant chipboard is very good stuff and is designed for flooring, unlike OSB. I would assume it’s a bit cheaper as well and with the T&G it’s easy to glue.

I put 25mm insulation between my battens (I think the battens are 38mm). In a side room I skipped the insulation and there’s a noticeable sound difference; it sounds like a solid floor where there’s the insulation and has a hollow thud in the bit without. The side room is also on different centres so there’s a noticeable benefit to going 300mm. I’d do it exactly the same again next time. The only downside with the 300 centres is it’s a pain in the tits cutting the insulation into such thin strips.

[Magooagain]

zbc said:

Magooagain said:

What does the estimate (Devi) actually say?

Dépose de l'ensemble du plancher bois, y compris évacuation des déchet
Fourniture et pose de panneaux OSB22, y compris remise à niveau du support

Speaking to the plasterer on site at the moment he suggests screwing battens to the floor to get a level and laying the OSB ontop

So they are proposing to remove and dispose of the existing boards. They will then lay the osb on the floor timbers but make sure all is level.

My observation based on the photo is that it’s a good idea to get those floor boards away for a few reasons. They are probably all rotten or some of them are. You will then have access to be able to wood worm treat the timbers below also insulate. The window sills are close to the floor now so if it’s batons on top of those existing boards then osb plus finish flooring you could be very close to the window cill board.

Beware of extras cropping up. In the photo at least one timber support is pitched onto the floor so that will need dealing with.