Felt Flat Roofs
Felt roofing has a very bad reputation. This is because many years ago this material was a really bad choice. The felt was often prone to rot and tended to dry and become cracked from the sun. If you were lucky you might get ten good years out of it.
Torch-On Flat Roofing Felt
Modern felt roofing is torched on instead of the old pour and roll method. And a lot of great progress has been made in the actual felt too. Nowadays it is much more resistant to UV rays and doesn’t dry and crack as easily. The back of the sheet is heated with a torch and then rolled on to the roof structure.
Also nowadays there are usually 3 separate layers applied which each serve a different purpose and all result in a much more insulated and durable rough.
It’s very strong and very durable when installed correctly and the top layer is available in many different colours.
Almost any roofer will give you a 10 year guarantee because they know if it’s installed properly it will easily last 20 and possibly even 30 years.
- Price – The most affordable flat roof option
- Appearance – Lots of different colours to suit all tastes
- Usability – Useful for any size of roof and suitable for complex roofs with various details, not suitable for heavy foot traffic
- Durability – Can last for 20 years plus if installed correctly, good expansion and contraction properties make it resistant to the elements and UV rays, can be walked on but not too frequently
- Ability to Repair – As easy as adding a new area of felt to the torn or worn area
- Other Issues – As it requires a flame torch to apply you should make sure your roofer carries the proper insurance cover
Asphalt Flat Roof
Asphalt roofs have been used for quite a long time now. But just like felt roofs, with modern innovations they have become significantly better.
Asphalt can be laid on timber metal and concrete. It’s very heavy so it does require a strong structure. But it is very versatile and can be used on roof designs that are fairly complex, easily fitting around vents, roof lights or slopes etc.
- Price – On average expect to pay about 20-25% more than a torch-on felt roof
- Appearance – This is really down to individual tastes but it has a matt grey finish which many like the look of
- Usability – No need for flame torches, but does require a strong structure and not suitable for heavy slopes, suitable for roofs with complex detailing
- Durability – Extremely hard wearing, can easily withstand heavy footfall, some asphalt roofs can last 40 or 50 years only requiring some light repairs
- Ability to Repair – Repairs are quick and easy, and there are many different options of material to repair it with
- Other Issues – The underlying roof must be strong enough to not flex, otherwise the asphalt can crack, also the substructure must not have any rising damp or complications may occur in the asphalt
EPDM Rubber Flat Roof
These roofs have become much more popular in recent years. EPDM (Ethylene Propylene Diene Monomer) is a large roll of rubber roofing material. Due to its width it can often be installed in one section meaning there are no joints. It is also very light and straightforward to install as they don’t require flame torches. They can simply be glued down to a wooden substate.
The main benefit of EPDM roofing is that it lasts an incredibly long time. If it’s installed correctly it would last as long as 50 years.
- Price – Affordable but still about 25% more than a torch-on roof, but a small roof could be installed by a DIYer
- Appearance – It’s looks like you would expect, a black sheet of rubber, some people like it but others don’t
- Usability – This material is best suited for simple roofs, if there are too many complications it can look poor and also be more prone to leaking
- Durability – As you would expect, it’s very durable and can withstand all types of different weather and wear and tear, is susceptible to damage from pointed objects or vandalism from knifes
- Ability to Repair – Can be repaired quite easily using more patches of EPDM
- Other Issues – Needs to be fitted by competent professionals, it can be prone to shrinkage so fleece-backed EPDM is recommended on large roofs areas, russ strips are also necessary to prevent edge details pulling away from the walls from shrinkage
GRP Fibreglass Flat Roof
GRP (Glass Reinforced Plastic) is another type of felt roof material that has become much more popular recently. This is largely due to the improvements in both the material itself and the newer more reliable installation techniques.
Being completely jointless makes it an excellent choice
A fibreglass roof should easily last 20 years and even up to 30 years when high quality materials are combined with expert installation.
- Price – It will depend on the exact spec you go for but expect to pay a bit more than an EPDM roof
- Appearance – With so many colours to choose from this is probably the best looking type of flat roof material
- Usability – Very light and strong, comes in a huge array of colours, works well only both very complicated and simpler roofs, only downside is that it’s not really suitable for use on a very large area where the structure is prone to contract and expand excessively or where the structure might not be very strong
- Durability – Extremely long lasting and super strong, resistant to almost any type of damage or vandalism, can be quite slippery when wet but there are special anti-slip coatings that can be applied
- Ability to Repair – Repairs are quick and easy but also basically invisible once completed
- Other Issues – Requires good, dry weather to install properly, don’t skimp on the material quality, make sure it’s from a reputable manufacturer and is thick enough
Single Ply Membrane
There are many different types of single ply membrane. Technically it’s any roof covering that can make a waterproof flat roof with just one layer.
The most common types are PVC, PIB, TPO and TPE.
All single ply membranes share similar traits with some minor differences separating them. For example they are all light, very flexible, very resistant to all weather types from very hot to very cold. They are also able to handle UV light and are resistant to mold and mildew growth. Finally they are fire resistant (and in fact self-extinguishing), chemical resistant and friendly to the environment.
This is why they are so commonly used on commercial and industrial buildings.
However for a residential setting single ply membranes are usually overkill and are also more expensive than the other options available.
- Life expectancy of over 30 years, sometimes up to 50 years
- Very expensive
- Durable and easy to install
- Not resistant to solvents
PVC (Polyvinyl Chloride)
- Life expectancy of over 30 years, sometimes up to 50 years
- Slippery when wet
- Prone to shrinkage
TPE (Thermoplastic Polyolefin Elastomer)
- 100% recyclable
- Expected life of 30 years, usually guaranteed for 20 years
TPO (Thermoplastic Polyolefin)
- Environmentally friendly
- Expected life of 20 years, guaranteed for usually 15-20 years