Measuring T&G chipboard floorboard thickness

[btjtaylor]

Hi all

My house has T&G chipboard floorboards (evil things!) and I need to replace a damaged section

There seems to be 2 common types 18mm and 22mm thickness

I used a vernier caliper and its coming out as 19.68mm

There's writing on the bottom of the boards "PELLOFLOOR FLOORING GRADE TYPE DC" but no thickness written

I'm guessing I should go for the 18mm variety?

Thanks in advance

 

[Deleted member 174758]

One possibility is that the flooring was nominally 19mm as supplied. At one time flooring grade chipboard sheet was nominally 3/4in or 19.05mm thick, supplied as 8 x 4ft or 2440 x 1220mm sheets - no T&G. These days it generally comes as 2400 x 1200 T&G panels.

There's also the possibility that the flooring has swelled a little, which can happen in bathrooms, kitchens and entrance halls if it isn't a moisture-resistant grade (P5 grade, often greenish).

The repair sections can be shimmed a millimetre or so on packers or the new chipboard can be fixed to the existing joists and the top levelled with a skim of SLC afterwards. Ensure that all your joints are adequately supported (if needs be using additional noggins or solid strutting) and tbat you leave a 10mm expansion gap along wall edges (this will be covered by the skirting). Current thinking is that chipboard sections should be glued at the T&G joints as well as to the tops of the joists with a D4 flooring adhesive and that screws should be at no more than 300mm centres

Personally I'd go with 18mm glued and screwed to the joists with a skim of SLC on top (primed first) to bring it all level as being the least fiddly to do the job

 

[btjtaylor]

Thanks for the really helpful reply, it's in the bathroom so I reckon it's either 18mm that has swelled or 3/4in originally - possible as the house was built in 1979, that's before my time but I'd imagine a lot of materials were still sold in imperial measurements? The builders seem to have been working in imperial at least, as my joist centres are bang on 16 inches (40-ish CM).

I will go for 18mm and pack it slightly if required.

 

[JohnD]

Chipboard is an awful material

You may do better to replace with ply. Paint or varnish the edges after cutting to resist water

Add struts or noggins under all unsupported edges.

 

[Deleted member 174758]

Thanks for the really helpful reply, it's in the bathroom so I reckon it's either 18mm that has swelled or 3/4in originally - possible as the house was built in 1979, that's before my time but I'd imagine a lot of materials were still sold in imperial measurements? The builders seem to have been working in imperial at least, as my joist centres are bang on 16 inches (40-ish CM).

I will go for 18mm and pack it slightly if required.

I think 1979 makes it more likely to be 8 x 4ft sheets of 3/4in material. If your joist centres are about 406mm (16in) that confirms it - for modern 18mm T&G stuff you have to work to 400mm centres.

If you replace with chipboard I'd recommend going for a moisture resistant grade (P5). Unlike John I have no problems with chipboard (providing the right grade is used and it is installed correctly)