Joists in new flat roof getting wet

[djaychela]

In short, ground floor extension with flat roof... it can't be roofed properly until the dormer is built, which won't happen for a while due to delays and weather. So I now have a load of joists that I've fitted, which are getting wet in the rain. I've put DPC over them to try to stop them getting wet, but it's just absolutely hammered down and I'm concerned that if they stay like this I'll end up with a set of bananas instead of a nice flat roof.

Should I be looking to buy a load of (eye-wateringly expensive) OSB sheet or similar and sheet the roof temporarily so I can protect it? Given the weather forecast, it's going to be a few weeks if not more until I can get the old dormer stripped off and the new one built.

 

[Swwils]

Scaffold and tarp would probably be cheaper

 

[djaychela]

I take it that it's needed then?

 

[Swwils]

Depends really on how long your unknown delay will be.

 

[thomp1983]

If it's the black polythene visqueen type dpm you've covered it with then that will be fine as long as its properly held down.

my flat roof that is boarded has been covered in it for at least a weeks rain to keep the boards dry and it's been absolutely fine as we keep removing it to do a bit more in between the weather

 

[catlad]

Not much of that makes sense! just get on with the job.

 

[^woody^]

Temporary board it with the boards or insulation sheets you would be buying anyway, and these will keep the polythene flat and draining properly.

Don't let water run down the walls.