Rotten Floor boards

[DIY_Johnny]

Hi this referes to my post in the tiling section. I recently took up a kitchen and bathroom floor. In the kitchen there was cheap laminate laid on top of underfelt on top of the floor boards. In the bathroom it was floor tiles on 12mm plywood. Any bothe were soggy due to (seperate) leaks occuring for years.

Here is a photo of the floorboards in the kitchen and bathroom. Apart from removing / replacing the rotten floorboards is there anything else i shoul;d be concerned about. Some of the joist are like this too but the are theer simply to support the floor. There is a load bearing slabe underneath and between the joists.

When I removed the laminate / tiles it was all wet and soggy underneath, it has dried out somewhat now

Any thoughts chaps


cheers

[ultimatehandyman]

That is wet rot.

I'd remove all rotten pieces and then replace with either new boards or WBP ply.


Give the joists time to dry and then treat with wood preserver.

[ultimatehandyman]

Forgot to ask how much of the floor is damaged?

[DIY_Johnny]

ok I was wondering if the white stuff was fungus and thus dry rot which may have spread top teh joists
In the bathroom I'd say about 50% is like that so I might remove it all and replace witrh 25mm ply as you suggest.

In the kitchen, about 30%. If I remove all the boards I could reuse some of it as ther are lots of little bitty pieces of floor boards all over the flat where they have been cut to get services in. Edges are all frayed so hard top renail / screw down

How much time do you suggest, few weeks?

[leebwk]

Hi John,

As Uhm has said that is wet rot and you need to remove all the affected areas replace with either WPB ply or Green chipboard and replace damaged joists with tanalised timber, also make sure that ther is ventilation under the floor (i presume this is a ground floor?)

[DIY_Johnny]

Ok will do, actually its a 3rd floor flat the buildings appear to be constructed with concrete slabs with floor joist laid on top and infilled with more concrete as a fire protection. At least thats what we think. Its hard to tell from the picture but there is only a 2 inch gap below the floorboards to the concrete. Problem is that a few of the joists (top part) are rotten aswell so its dificult to screw plywood into the joists.

I presume I can lay a 2" batton across the joist resting on the concrete to provide a bit of extra stability / support although I'm not entirely convinced about method of construction of the flat. circa 1930's

Not sure how to provide ventilation is such a floor as any holes to teh outside would let rain water in (from the fire escape).


PS whats tanalised timber? whould this be ok
http://www.wickes.co.uk/P4S+Regularised ... nvt/107088

[leebwk]

Yes that timber is fine