Flat roofing materials

Flat roofing material on a terrace extensionIf you’re reading this article the chances are that you’ve a flat roofing issue on your mind. Your might be planning an extension, home garden project or simply looking to replace an older flat roof. There’s a lot of choice out there and deciding on the best option for you is a balancing act between cost, durability and flexibility.

After a few ‘flat roof’ related Google searches you’ll find a multitude of flat roof materials are available, offering a range of attractive features and coming with a range of price tags. Some are DIY-able, others you’d be better hiring a flat roofing expert. We say flat roofing expert because general roofers might not have the specialist knowledge required to fit a flat roof correctly. This comes with skill and experience so you want to chose your roofing contractor carefully. It you want to reap the benefits of a flat roof it must be fitted properly, otherwise you leave yourself open to a whole host of issues.

In this article we hope to explain a few of the main types of flat roof & offer a little help in choosing which type of flat roof might be best for your needs.

But first, in case you’re still on the fence between getting a tiled or slated pitched roof and a flat roof let us explain why we think flat roofs are best.
The main benefit of a flat roof is its low maintenance and high durability. Once a flat roof is installed you can pretty much leave it alone and it’ll hold fast whatever mother nature throws at it (in the UK at least).
Flat roofs are generally cheaper than tiled/slate roofs- taking installation, maintenance and repairs costs into account, flat roofs are versatile- you can have a roof garden, a balcony, or simply easy access to your first floor windows and gutters and they’re quick to install. If you want to talk to the experts in flat roofing, Northern Roofing Solutions Ltd, an authority on types of flat roofing in Liverpool would be happy to take your call & help you with your flat roofing question.

So, the next question to answer is- which material will be best for your flat roof?

Types of flat roofing

Felt & Asphalt

Felt flat roofing
Also Known As: Felt Paper, Asphalt Felt Paper (similar to tar paper)

Pros: Cost effective, works well within it’s lifespan

Cons: Degrades quicker than other types of flat roofs, limited aesthetics, exposure to the sun can reduce its lifespan

There are a range of types of felt roofs so lets start with the earliest one we’re going to cover- Mastic asphelt. Asphalt is more commonly known to be used in road and pavement construction but its also a useful roofing material. This material was used in the early 20th century as it worked well on buildings made with dense, bonded material due to their limited movement. Mastic felt isn’t very flexible, movement, especially in cold weather when it can become brittle, can cause it to crack.

In the 60s & 70s people started to use Mineral Felt as it was an inexpensive and quicker alternative. It consisted of pouring and rolling hot bitumen over the roof and was sealed at edges and joints. It had a life span of around 10 years which would be reduced if it was used for access to windows and gutters. Its bad reputation is partly due to poor workmanship. As many roofers were paid per job (piece work) and a quick job meant more money and so jobs were often rushed.
Next came Torch on Felt roofing which came in the form of a kind carpet which you would torch on the underside to make it sticky to it’d stick to the substrate (the underlying timber).

Felt is commonly found on garage and shed roofs, they’re quick to install, are lightweight and the cheapest option for flat roofing projects.
However, they have a short lifespan of around 10 years and are prone to weather damage, becoming soft and pliable in hot weather and brittle in cold weather. It can still be a good solution for small projects though, especially garden buildings, tool sheds and garages.

GRP roofing

GRP flat roofing
Also know as: fibreglass roofing and glass reinforced plastic.

Pros: Durable, light weight, resistant to corrosion, cost effective, suited for smaller roofing projects

Cons: Needs dry weather to install (might be a struggle in the UK!), expensive, inflexible

GRP, or Glass Reinforced Plastic, is a very popular flat roofing solution for many domestic jobs as well as small to medium sized commercial roofing projects.
Fibreglass flat roofing is very strong and durable, it comes with a guaranteed warranty of 20 years but its life expectancy is in excess of 40 years if properly maintained. GRP roofs are weatherproof and so are at little risk of leaking or developing frost damage.
Their durability also makes them very good for footfall, which can be useful if you plan to use your flat roof for access to first floor windows and gutters.
To give you an idea of how tough GRP they’re also used for the hulls of some boats which can withstand years of rough sea conditions.

If you want an elegant looking flat roof GRP is a great options. Grey is the most commonly used colour and gives your new roof a lead-look. You can also get it in a range of other colours but you’ll pay extra for this option. You can also get a range accessories for GRP roofs such as trim, tilt fillet, outlets and cappings which can give the roof a tidy and elegant finish.

So GRP is durable, long lasting and very tough. The main downside is that they need to be installed in dry conditions and so summer time is best for this kind of job. It’s also pretty inflexible and so you need to build on a dense and bonded structure to limit movement. It costs more than felt and rubber roofing but it’s worth the extra money if you can stretch to it.

Rubber roofing

Rubber roofing example
Also know as: EPDM, ethylene propylene diene monomer, waterproof felt, single play membrane roofing

Pros: durable, flexible, cheap to repair, cost effective, weather proof
Cons: Easily damaged/vandalised, risk of joint glue contamination, expensive

Rubber roofing is a type of single ply membrane roofing, we know we’ve covered single ply membranes in the next section below, but rubber roofing is particularly popular and so we though we’d give it special attention. In short single ply membrane roofing is a single layer of water proof roofing material. They’re lightweight, quickly installed and cost effective roofing systems which are produced to very strict manufacturing quality control requirements making them increasingly popular in both domestic and commercial roofing.

Rubber roofs are very durable and long last coming with a 20 year warranty and a life expectancy of over 25 years. EPDM comes in a variety of grades and the higher the grade the better quality the material. It’s glued directly to the timber roof structure and joints are glued together making this type of roof very waterproof when it’s in good condition. It comes in a small range of colours, grey shades being the most popular and so its also the cheapest.

There is the risk of contamination of the glue used to bond joints with EPDM roofs. If they become contaminated with dust or water it can reduce their effectiveness and can lead to roof failure.
This material cannot be recycled it can however be reused if it’s laid loose and mechanically fixed to the underlying roof structure. Due to it’s small disadvantages EPDM is the cheapest single ply membrane material. Making is a very viable option for roofing jobs for the home and garden.

Single Ply Membrane

Single ply roofing material
Also Known As: Upside-down roofs, protected membrane roofs

Pros: lightweight, cost effective, flexible, durable, weather proof, mostly simple to install
Cons: usually not recyclable, often requires very clean installation,

Single ply membrane roofing is gradually becoming a very popular roofing solution for homes, gardens and businesses. It’s main benefits come from it’s long-lasting durability, ease of installation and cost effectiveness. There are a range of single ply materials available coming in a range of colours and with a variety of joining or fixing methods making it a viable choice for most budgets.

Single ply membranes are ideal for all roofing projects including new builds, refurbishments, flat, pitched or curved roofs, garages, extensions, conservatories and dorma conversions.

PVC. If you like simplicity and choice PVC is a great option for you. It can’t however be laid over bitumen unless an isolating layer is installed first so if you’re replacing a felt garage roof you’ll need to take this into consideration. It also contains plasticiser and chlorine making is a bad choice if you want to be environmentally friendly.

TPO (Thermoplastic polyolefin) is for those of you who want to do their bit for the environment without paying a hefty price. it can be partially recycled and doesn’t contain plasticisers. The range of colour are limited to greys and life expectancy is a little lower but its still a very good option.

TPE (Thermoplastic Polyolefin Elastomer) is the next step up in environmentally friendliness. It’s 100% recyclable with much simpler installation, quick and easy to repair, even small holes without the need for patches. You’ll pay a little more for this type of membrane though, but at least you can feel good about it.

PIB (Polylso Butylene) is the most long lasting single ply flat roofing solution, still going strong after 50 years! It’s so environmentally friendly that it’s full life cycle, from manufacture to recycling, has a very limited effect on the environment. What’s more its easy to install, durable and very cost effective.

To bring the main pros and cons of each flat roofing material we’ve covered in this article we’ve created a venn diagram. It covers durability, flexibility and cost effectiveness. We hope it helps display how the options pan out.

Flat roofing material comparison

If you want to discuss your particular roofing need with a professional and friendly flat roofing specialist just contact Peter at Northern Roofing Solutions. Consultation and initial estimated cost is a completely free service, accurate quotes are only given after a complete survey has been carried out.

Posted in Roofing Matters

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