Replacement subfloor materials

[limawhiskey]

Due to water damage from a slow leak, I have had to take up the floor in my girlfriend's bathroom. I now want to find the materials to renew it but not sure where to source them. The subfloor has several layers, I assume this is for soundproofing as it's a first floor flat.

The floor layers are (top to bottom):

• Tile
• 4 mm ply/hardboard
• 18 mm T&G chipboard
• ~17 mm gypsum product
• 25 mm insulation
• 18 mm OSB board
• 9" x 1.5" joists

The replacement wood should be easy enough to find. It's the layers in bold that I'm not sure where/what to buy. The gypsum product is labeled "British Gypsum" but looking at their product line I can't see anything that exactly fits the purpose.

The insulation looks like standard fibreglass stuff, though obviously not as deep and more dense. Is there a specific product for flooring?

Photo shows the gypsum and insulation layers:

The other factor is that the floor is at least 10 years old so there may now be another solution.

Any advice would be appreciated

 

[limawhiskey]

I'm going to use 19 mm gypsum plank to replace the all the gypsum layer but I'm still having trouble finding a suitable replacement for the insulation.

Any opinions on whether something like 25 mm polystyrene would be ok?

 

[ree]

What i see in the pic and what is in your layer's list doesn't correspond.

Layers of plasterboard are often used for sound proofing floors. They are usually laid across the joists in 8ft x 4ft sheets.

Whatever, you can make up the layers of missing material in any rough dimensions to suit. What is important is to have the final sheet of sub-floor material flat and level with the in place sub-floor (chipboard).

 

[limawhiskey]

Thanks for the reply.

The photo shows just the gypsum board and fibreglass insulation - the tape measure is resting on the OSB board. The chipboard and other layers above the gypsum have already been removed.