Waterproofing a corrugated garage roof?

[brettbuckley]

My garage roof consists of a number of corrugated panels, bolted onto wooden joists which run across the width of the garage, from front to back.
The roof gently slopes from front to back where it leads to a gutter to collect the water.

I believe that the panels are made of cement / asbestos mix and they are still sturdy and in good order.

However, the roof leaks during times of heavy rain which inhibits me spending any time and money sorting out the interior of the garage - it seems to leak where the panels join and have bolts driven through them.
Once I have sealed the exterior, I plan to PVA the interior and cover with masonry paint or something similar.

Can anyone please suggest a quick and cost effective way to fix the exterior?

Many thanks...Brett

 

[Deluks]

There should be rubber 'upside down cup' washers under the bolt heads which waterproof the bolt holes. You should probably acquire some of these and redo each bolt in turn. If it leaks at the joins then you may not have enough overlap, should be at least 2 corrugations overlap.

Could also be hairline cracks in the sheets or simply condensation.

If you go up there, scaffold boards a couple of sheets of thick plywood or similar are essential to walk on.

 

[Cumbrianroofer30yrsexp]

My advice would be remove it a fix plastic coated box profile sheets.Its a very straight forward thing to do.

 

[ladylola]

I'd also remove the climbing plant as it will restrict the flow of water and cause it to back up the joints

 

[brettbuckley]

Thanks for the replies folks. I spent some time at the weekend using a water jet to blast away the accumulated moss (nearly a bucket full in all!)

In doing do, the water soon started to leak through the panels and I could then see that the moss caused this by restricting the drainage of water and causing it to build up and then flow back up the sloping roof and down the joints, as ladylola suggested.

Next job...remove the ivy.

Thanks...Brett

 

[datarebal]

sealoflex...

 

[Cumbrianroofer30yrsexp]

Plastic coated box profile sheets,made to measure,each sheet being the length of the roof,no over laps,litrally last a life time.A grand would cover it,enough change for a pint if you haggled and paid cash.A compatent DIYer could do it himself for a fraction of the cost..

 

[Mw Roofline]

Remove the sheets and place some 16mm poly on the roof with some snap fix glazing bars, piece of cake and looks nice.

Cheapest on ebay

http://cgi.ebay.co.uk/Polycarbonate...ocalservices_tradesman_GL&hash=item27b10061d2

I reckon 600 quid will do that roof

 

[i_am_fubar]

my current favorite... Bitumen paint. Would definitely waterproof it. But I don't know how it would react heat/UV/temperature... etc.