EPDM over old decking

	This is an old felt flat roof, probably laid 10 - 15 years ago. We were asked to replace it because it was leaking. Note the peeling edges. Also the stones have slowly washed to the centre of the roof. You cannot see the centre gutter as it is full of stones.
	Now that the old roof is nearly stripped away, the old decking is exposed and you can see the centre gutter.
	The roll of EPDM rubber roofing has been cut to a rough size and is being laid out prior to fixing.
	Now the glue has been applied and you can see some shape definition.
	This is the finished roof  with the metal edging trims added to the side.
	This shows the  metal dressing trim that is part of the roof system. A roof like this will carry a 20 year insurance-backed guarantee.

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Related Questions

 

Q) What's the point of the stones on the old roof?

A) They are for solar-reflection, to keep the roof covering cool, also they are ballast to keep the roof down and in place. EPDM rubber roofing doesn't have a problem with heat, so no solar stone covering or paint is needed. It's also stuck down so there is no need for ballast.

 

Q) Is the old decking OK to re-use?

A) Yes, in this case the decking was in very good condition after we cleaned it up. Sometimes it has rotted away and we have to replace small areas.

 

Q) Is old decking the best thing to lay EPDM over?

A) If we had the choice we would replace the decking with "sterling board" as this carries a BBA certificate that means it has been tested to withstand the conditions it's being used in.

Q) How big are the rolls of EPDM?

A) A roll is 3m wide and 15m long. This size is just about manageable by two men. Bigger rolls are available but we only ever use them on very large projects because of the cost of moving them.

Q) Can you join the rubber sheets?

A) Yes, we use joining tapes and cover strips that have been designed to work with the system. The complete system has been tested and has a BBA certificate. The life span is expected to last more that 40 years.

Q) What about it getting cold and brittle?

A) It's been tested down to -40°C and is still malleable. Samples have been removed from roofs that are 40 years old and the samples have only demonstrated a 10% loss of elasticity.

Q) What are the metal edging strips?

A) The metal edging strips are galvanised steel with a plastic coating. They are designed to work with the system, replacing the old lead flashings that are heavy and bulky.