I would recommend using grp system for flat roof as it s a more robust material compared to felt or epmd rubber.
Flat roof grp or felt.
Grp is a very tough material that can withstand falling branches or a dislodged tile slate falling off main pitched roof onto your new extension flat roof unlike felt or epmd.
Felt and grp fibreglass roofing systems are the most popular systems for flat roofs.
Grp roofs are less prone to damage than felt roofs and epdm roofs too.
The covering which makes them water tight can be achieved using various products with 2 standing out as the industries norm.
Given the greatly superior durability of grp roofing to felt systems you might think that a grp flat roof would cost a great deal more.
Its unique construction gives it waterproofing properties for one of the most durable flat roofs on the market.
In short any roof covering that can make a flat roof waterproof in one layer unlike roofing felt with its 3 layer system for instance.
Felt can only be applied directly onto a solid sound timber base as the base layer needs to be fixed to the boarding under no circumstances should felt be torched onto a grp resin roof.
The popularity for both systems stems from different requirements however.
Felt is a cheaper material fibreglass is more expensive.
This kind of peace of mind is hard to put a price on.
The first being a 3 layer felt systems and second grp glass reinforced plastic.
Grp fibreglass flat roofs.
This means that over the years the chances of repairs are lessened and in turn more money will be saved.
They are also suitable for pitched roofs in some applications.
This can include epdm rubber and fibreglass talked about above but commonly especially in the trade and in this article it refers to pvc tpo tpe and pib.
While felt may be the most traditional form of flat roofing grp glass reinforced plastic fibreglass is now becoming more popular.
Epdm is highly flexible and can cope with building movement.
Grp roofing vs three layer felt system the majority of all loft conversions will have a flat roof constructed to them.
They lasted a long time and were attractive to the eye but their performance was questionable.
Although grp is pricier than felt or epdm rubber roofing systems when you factor in this impressive longevity along with the lack of maintenance needed resistance to all weather and attractive laminated finish fibreglass roofs can be worth every penny.
This material consists of a layer of polyester resin which is reinforced with glass fibres to form a laminated layer.
This is not the case.
As a result a felt roof would typically only last 5 years or less.
Sleek clean appearance extremely moss resistant.
Felt is not capable of substantial elongation without failure.