Roof

kumarana

Hello,





I recently moved into a new house, and the garage roof needs replacement. I’ve noticed wet patches on the plywood. I’m attaching photos of the roof from both the inside and outside.





What type of roof would you recommend? The current roof has small stones on it, but I’m not sure what their purpose is. The timber frames appear to be in good condition.





Looking forward to your advice. Thank

grumpy_codger

I think, stones are to protect the felt from UV.

I recommend a proper pitched tiled roof if allowed, but this will be more expensive.

If it's a new flat roof, pay extra for EPDM. It lasts longer.

fisher66

Yes - the stones are to protect the roof from UV. It will be a bitumen felt flat roof and the felt will be decaying. I had the same and managed to patch up the holes for a few years but in the end I got a new GRP (fibreglass) roof installed. It looks a lot smarter and should last 25 to 30 years.

Grenage

I'd probably use EPDM as a replacement.

tacpot12

Another vote for EPDM. 

kumarana

Thank you, everyone.

If I opt for EPDM, how will rainwater drain? Currently, the gutter is located at the lower edge of the roof.

Do I need to replace the plywood under the roof as well

daveyjp

Better to strip back completely, new plywood and modern rubber roofing finish.  Fillets will be placed under one end to ensure a slight gradient to drain water.

The stones provide protection, prevent ponding and also increase the surface area of the roof resulting in faster evaporation of the water.

grumpy_codger

It looks like chipboard, not plywood. Not that it makes much difference.

TELLIT01

EPDM sheeting can often be supplied as a large single sheet, unlike felt which will have seams even if it is laid using heat to seal the joins.  The guy who did my shed roof said he'd done his own shed with a single sheet over 20 feet long.  He did say it nearly killed him getting it onto the roof. :-)

ThisIsWeird

Given that your garage has a nice surrounding parapet, so you cannot even see the 'flat' roof from the ground, it's astonishing that the original builder didn't add a more decisive slope to the roof! Make sure that is corrected!
Gently sloping roofs are not particularly attractive, but yours is hidden, so make damn sure rainwater shoots off a pronounced slope like a shooty thing. The current one looks as tho' water could actually pool near the top end - nuts!
As to the material to use, 3-layer (I think) modern felts should last decades, but still remains the "I can't afford better" option. EPDM is better, longer lasting, and better seam-sealed, but can be surprisingly prone to being damaged - a stone chip stuck to your boot could do this.

GRP is the ultimate.

Apart from coated metal sheet...

The rain will drain off as currently. The boards may or may not require replacing - almost certainly the roofers would want to rip it off leaving just the joists, add fillets (firrings?) to increase the slope, and reboard. 
Always - get at least three quotes from personally recommended roofers/builders.

stuart45

ThisIsWeird said:

GRP is the ultimate. 

Loses against copper and lead. (Until it gets nicked).