Flat Roof Types & Estimated Cost Guide
Flat roofing has come along way in the last ten years since the days of them just being a cheap alternative to a pitch roof and nearly always leaking. That has changed now and thanks to the development of better materials.
We live in a climate of consistent damp and wet and all roofing systems need to be able to cope with that certainty not to mention driving winds and unpredictable conditions. Our wind driven rain will test any roofer worth his salt. “Modern materials, design and ventilation have completely changed flat roofing” see more here, see more info below (Reference)
Flat roofs which should not not be totally flat as its needs to give a small fall in order to direct water using 1 degree fall to direct water to the gutter. Flat roofs are popular usually on rear or side extensions avoiding the need for an apex or pitch. With some buildings depending on where the windows are giving better views and vista.
Torch-on felt is what covers most flat roofs and has come a long way in the last ten years. This is the go-to option, cheap and readily available, it’s usually applied in two or three layers. They can either have a granular finish or a smooth finish and this can be then painted with solar reflective paint. It usually comes with a materials guarantee of 10-15 years and costs about €55per sqm.
Another alternative is PVC, this is a single ply membrane of usually grey-coloured rubber is fixed to your timber base, making labour costs cheaper than the installation of a two-ply material. When its laid well it can looks very good, it usually costs 20-30 per cent more than a torch-on system and will come with guarantees of around 12-15 years.
Then there’s fibreglass, its effectiveness is still a bit undecided but has a reputation of being durable. Its inflexible nature is not suitable for some situations, but advances in materials in recent years have made fibreglass roofing more reliable and very durable. Costs are around €70 per sq m on domestic-sized roofs and should be able to last for about 15-20 years.
Zinc is growing in popularity and one of our favourites, it’s a slick, smooth, contemporary look that goes on in panels with a standing seam joining each panel. Its a very modern and durable look impressing the neighbours and visitors.
It is naturally resistant to corrosion, needs minimal to no maintenance due to its natural, self-protecting patina, and is extremely long lasting – 100 years-plus. It can come in a few grey, dark and silvery colours and will maintain its colour throughout its life.
Costs are about €120 per metre by the time up-stands, drips and fascias are taken into account. It is a nice advantage to be able to do your fascias, soffits and rainwater goods in the same material, giving nice continuity and consistency.
Copper has been the more traditional way to go. It is one of the few metals that occur naturally rather than needing to be extracted from ore, thus making it one of the earliest metals to be used.
The covering of choice for well-to-do buildings of the past. The gorgeous green patina it develops after years of oxidation has long been coveted by architects.
A truly beautiful natural product but unfortunately it comes with a truly heavy price tag. Expect to pay in the region of €130 per metre. Like zinc, it is extremely long lasting, around 100 years in this country.
Lead, another beautiful and traditional product, is hugely malleable, and mostly used on small areas, over bay windows for example. Cost would be similar to copper at €130 per metre and comes with a material guarantee of 50 years.
Reference; Irish Times