What thickness flooring boards should be used?

[Mr_T25]

Deciding on what type of flooring to put down. Is 18mm panel boards ok to put down as the main structural flooring on the 1st and 2nd floor over the joists? It will take levelling compound and wet UFH and then carpet in room areas or tiles in wet rooms.

 

[John D v2.0]

Should be fine assuming you mean plywood and the centres of your joists are normal.

 

[Mr_T25]

Our joist centres are about 400mm apart. Is plywood durable for a structural floor? Are the tongue and groove boards any better?

 

[JohnD]

I use 18mm ply, screwed down, and am very happy with it. It is more durable and rigid than the chipboard rubbish I ripped out.

I used to lay softwood floors, quick and easy when you know how. I would say they are more inclined to show the joints and unevenness as they move with the weather. I don't know how the cost compares.

 

[Mr_T25]

I started questioning myself when a builder friend of mine said I should have used at least 22mm boards.

 

[JohnD]

did he mean ply?

Builders often use chipboard, which is very inferior, but usually lasts until after the cheque has cleared.

If you are replacing an old floor, use the same thickness to avoid steps, or gaps under the skirting.

 

[John D v2.0]

Agreed with Johnd, chipboard is just optimised to last the length of the warranty, we've had good success with 144x18 PSE wood from wickes where we had to replace existing boards, but for a new floor plywood would be more stable.