protecting flat roof from rain

[vivienz]

MBC are pretty much done now and it looks like my luck with the weather is about to run out as some rain is due next week.

I want to get a load of polythene that i can chuck over the roofs and anchor down to try and keep the worst of the rain off it. Its mostly the garage roof I'm concerned about.

Does anyone have any suggestions of what I should use?

[lizzie]

We used acres of polythene as it rained solidly for weeks after our frame went up. Will see if I can find where we got it.

[PeterW]

Use DPM from the likes of S’fix as it’s cheap and easy to get hold of. 

 

The trick is to make a tent - higher at the middle than the sides so rain runs off and doesn’t pool. Even a small hole then won’t let water in. Easy way is a couple of lengths of 4x2 down the middle of any roof and pull it taught down the sides and a couple of bits of timber and some long screws to clamp it. 

 

Contrary to popular belief, those blue woven tarps are not waterproof unless they are very tight. 

[vivienz]

Thanks, Peter. I shall swing by there on my way to the site tomorrow.

[vivienz]

@PeterW - is it possible to stick lengths of DPM together?  The widest DPM from SF is 4m wide but my garage is just over 5m.  What's the best way to cover this width?

[vivienz]

Ooo'! Don't worry - just found double sided membrane tape.  Problem solved.

[mvincentd]

How long do you think you'll need temporary cover?  This was monumentally stressful for me all last winter.  I started out thinking it was just a few weeks and so didn't put enough time and effort into the 'temporary' setup.  I ended up using 800sqm of dpm repeatedly trying different solutions and reworking it.  If you make a tent be sure to give it a good pitch so the weight of water...or snow..doesnt 'dish' the dpm into the framework and create individual swimming pools!