Meaning of T&G Floorboard 'coverage' size ?

[swebb99]

Hi,

I need some need T&G floorboard for a 1930's house, it currently has 5"x1" T&G boards. I look on various timer yard sites and they have boards of 150mmx25mm which is close enough, however they then state a 'Coverage' size which is usually something like 137mmx20mm. Now I can kind of understand that the tongue might be 13mm so reduce the width of the board but where is the 5mm going from on the thickness ? What does coverage mean ?

Example here: https://www.daviestimber.co.uk/products/REDWOOD-FLOORBOARD-25-X-150MM/P100342

Thanks in advice

 

[John D v2.0]

Timber is nominal sizes which are basically 4 by 2 and whatnot.
By the time they put the saw through it you've lost a bit, then for planed wood like floorboards you lose a few more mm. Then you end up with the odd finished sizes you see in the shops.

 

[swebb99]

Ah thanks for that. It would be a damn sight clearer if they advertised the real sizes then online searching would be easier.

Can't seem to find anyone who does actual 6x1 inch T&G floorboards. I would have thought there must be a fair call for them for people with older houses.

I suppose one option is to use none T&G where close sizes seem to be available. Not sure what gap to leave between them though and what the draft situation is, I'll be using carpet mind.

 

[big-all]

its actually the pre worked rough sawn quoted
planing 6x1"reduces it to around 21x143mm adding a tongue knocks it back by another say 8-10mm

 

[Nige F]

. Not sure what gap to leave between them though and what the draft situation is, I'll be using carpet mind.

No gap - fit them tight and they'll soon have a gap

 

[Doggit]

If you're intending to fit carpet, why do you want T&G. If you're trying to stop draughts, then either fit 22mm chipboard, or standard floorboards, and the hardboard; oh, and a good underlay works wonders - a lot of carpet fitters will tell you it's better to spend more on the underlay than the carpet.

 

[swebb99]

Hi yes the only reason for the T&G is because that is what the rest of the rooms have and I'll be patching about 8ft by 5ft of floor. Good tip about the underlay