Wrapping the ends of joists to prevent damp transmission (Ed.)

[Chameleonclaude]

I need to change many of the original floor joists due to rot. Typically joists are wrapped in DPM using stable gun for example.

I’m wandering if there’s a better way such as foil tape. Any thoughts would be most welcome.

 

[blup]

Address the causes of the rot, then they won't need to be wrapped in anything. Are they ground floor, upper floors, on joist hangars, over sleeper walls, in wall pockets?

Blup

 

[Chameleonclaude]

The joists sit inside a single skinned Bungaroosh wall in Brighton. The wall has no cement and a low content of lime. Frankly the houses here are shocking!

A mistake nearly all homeowners make is rendering their houses in cement mortar thinking that it will add strength to what is otherwise much like a digestive biscuit. The problem is that cement doesn’t breath and the lime walls cant periodically dry out. The cement render also doesn’t allow for any movement.

In many ways lime is the perfect building material as during wet months the building can make minor adjustments to the hilltop land which moves over time.

So my sloping floors all need to be levelled and given that there is some evidence of rot at the end of some of the joists I’ve chosen to renew everything.

I appreciate your interest and would still love thoughts on different wrapping methods

 

[sjee6]

I have the same issue, I was thinking about using felt.

 

[mcprinter]

DIYer
Have recently replaced a rotten ground floor joist for a neighbour. Leaking pipe.
Roll of DPC was £5-10

Pretty much did this. Quite easy.

 

[Notch7]

I’m wandering if there’s a better way such as foil tape. Any thoughts would be most welcome

I would use bitumen flashband -warm it up, stick it on then use a seam roller and a heat gun to get it nice and bonded to the joist

this method is used for fence posts and it significantly increases lifespan -they are called postsavers

Fence Post Rot Protector Sleeves | Postsaver Pro-Wrap

Postsaver's fence post sleeves guarantee wooden fence posts from rot and decay for 20 years. Get your fence post rot protection today.

www.postsaver.com

DPM plastic will be hard to fit neatly and it will leave gaps for condensation to get in

 

[tomm12]

You can use DPM or 12" DPC or even doubled up plastic rubble bags. And galvanised clout nails instead of staples. Some leave the top open for air but if the rot was dry rot thats not a good idea. Spores might be hanging around and could re-infect the joist. Always cap the joists after rot or damp repairs.