Insulation on Flat Roofs & how they can be installed

There are 4 common types of flat roofs.

•        Non Insulated Roof
•        Cold Roof
•        Inverted Roof
•        Warm Roof

A Non Insulated Roof has no insulation and is typically something like a garage where you have the structural deck and the waterproofing goes directly onto this deck. This can only be used for buildings that have no heat in them. If the building is heated there are regulations on renovations and new build that have to be met for u-values.


A Cold Roof is one of the most popular ways to insulate a roof as the insulation goes between the rafters / joists in the roof. A cold roof isn't as easy to get the same u-values as a warm roof or inverted roof as the wooden joists and rafters aren't as good at insulating as the insulation is. The build up is waterproofing layer directly onto the deck with insulation below with a vapour barrier attached to the joists with a ceiling installed below. They usually have an air gap between the insulation and deck for ventilation.


An Inverted Roof is where the insulation is above the waterproofing layer. It is typically something like a balcony where you have the structural deck, then the waterproofing membrane directly onto this deck, then an Extruded Polystyrene protects the waterproofing before paving or decking. This allows regular access to the roof. So no vapour control layer is needed as the waterproof membrane is on the warm side of the insulation acting as both the waterproof layer and the vapour control layer.


A Warm Roof is by far the most popular flat roof installation type, it uses structural decking, a vapour control layer, insulation and a waterproof membrane.

A critical part of the warm and cold roof build up is the Vapour Control Layer and how well it is installed. (See our vapour control layer document here)

The vapour control layer is there to prevent warm moist air from the inside of the building meeting cold air from outside. If the moisture in the warm air was to meet the cold air this would form condensation at the dew point (usually at about 3 degrees celsius) This will occur within the insulation layer and without a vapour control layer being present would cause condensation to form which would eventually lead to the timbers starting to rot.

Click here for our full range of Insulation and Vapour Control Layers

The Risks of Condensation & the effects of a Vapour Control Layer 

One of the most common problems now found with flat roofs is with the risk of condensation. This is where, in the past, many have blamed EPDM, Felt, GRP etc on their roofs leaking and this has earned flat roofs a bad name with some people and insurance companies too, but if constructed properly they can outlast many other roofing systems including tiled roofs.  A well constructed flat roof should last as long or longer than the BBA certificate it's been tested for so long as the manufacturers guidelines are followed. (For more information on BBA certificates on EPDMS please see our blog post here)
In this blog post I am going to explain the importance of a vapour control layer and how installing it incorrectly or not at all will result in a failed roof.  And let me also point out this can and does happen in walls and pitched roofs as well.

Firstly let's look at the technical aspects of itCondensation in a roof, or any structure for that matter, happens where the hot air from inside the building meets the cold air from outside at the dew point (the same as you see on grass in the morning). Another example would be if you were to blow warm air onto a single glazed window such as in your car in winter, condensation forms on the inside of the window and drips down the window, fortunately your car can be ventilated so that moisture that forms warms up and evaporates.  If we do the same to a double glazed panel this no longer happens because the air is sucked out of the air gap between the two pieces of glass and sealed. If there is no moisture in that gap then condensation can't form at the dew point. When the seal between the two panels fails moisture can get in and condensation will form.
   
This is the same for a building and the dew point is usually found within the insulated layer. This is why it's so essential to have a vapour control layer that is well sealed as this is the part of the roof build up that prevents moisture from forming in that insulated space between the vapour control layer and the waterproofing membrane. So even though the dew point still occurs within the insulated zone of the roof, if there is no moisture at that dew point then no condensation can form.
In essence, if there is no vapour control layer or its incorrectly installed then you end up with condensation and moisture forming at the dew point in the roof space which can then result in the roof failing through rot. Therefore to have a correctly fitted and sealed vapour control layer is just as important as having a good quality waterproofing membrane on top.
   
To give you a couple of examples here are some of our findings on jobs that we have helped on in the past.
On a recent consultation we were asked to investigate a rotten roof that had only been installed 7 years ago.
The build up of the roof was a cold roof (mentioned in this article) with the vapour control layer nailed to the underside of the roof joists prior to installing the plasterboard. The joists were filled entirely with rock wool, the structural deck was nailed to the joists and an EPDM membrane was fully adhered to the deck. Then there was a decorative hardwood timber tile to form an accessible deck so that the customer could use the space as a balcony.
The customer noticed the hardwood tiles were making a strange cracking noise which turned out to be the structural decking giving way underneath.
We first checked the EPDM for any sign of damage and to make sure it had been installed to the manufacturers guidelines. There was no damage to the membrane and it was a good installation.
We then checked to see which type of structural decking had been used, it was an exterior grade plywood which is the correct type to be used in flat roofing.
Next we cut 2 investigation holes in the plasterboard ceiling to check the integrity of the vapour control layer. It was a recognised and approved by the roofing manufacturer for this type of installation.
Upon further investigation of the roof outside we noticed that the worst rot appeared to be at the front of the roof so we cut one more hole in the ceiling and found the cause.
The vapour control layer hadn’t been sealed against the building structure with the manufacturers tape. This small gap allowed the warm moist air from inside the building to meet the cold air from outside and the result was condensation and a rotten deck. So even though a vapour control layer had been used the fact that it hadn't been fully sealed as to the manufacturers guidelines it still allowed warm air with moisture into the roof space allowing condensation to form at the dew point (i.e. the decking) and rot the timber deck.

On another investigation we were tasked with finding the cause of a rotten ceiling in a kitchen.  We first asked for a set of drawings and found there was a vapour control layer specified again at ceiling height.
When we cut into the rotten plasterboard ceiling we found no vapour control layer had ever been installed. After explaining to the client about the effect of vapour control layers and the problems that are caused by not having one the roof had to be re installed due to a large amount of damage to the timbers, decking and plasterboard's.

Hints & Tips

• A very handy tip that we got taught many years ago is that the vapour control layer should go on the warm side of the insulation.
• Always make sure that the vapour control layer is completely sealed around everything and anything. (i.e. walls, openings, wires etc.).
• If there are any punctures in the vapour control layer use the manufactures guideline to seal it back up, whether its tape or a patch.
• Our favourite and we personally think the easiest method of avoiding problems is to put the insulation board on top of the roof and use a self adhesive vapour control layer such as ALUTRIX onto the decking. This installation method also gives the best U-values as the whole roof is then insulated and not just between the rafters and roof joists.
• Also remember that if you are using insulation boards try to stagger them on the roof for the best results

.

Click here for our full range of Insulation & Vapour Control Layers 

Do green roofs need to have a stone border?

Do green roofs need to have a stone border?

If you are thinking of installing a green roof, you might have noticed that they often incorporate a stone or gravel border. You might well wonder why this is, or whether it is essential to a green roof build up.

There are a number of benefits to consider including:

• Stops the roots trying to get under the waterproof membrane at the edges.
• Access – Plants and Sedums aren't intended to have foot traffic.
• Aesthetic’s – Some people find a border neater at the edges of a green roof.
• Wind Resistance – the border can be heavier and helps with the roof edge in windy locations.
• Fire Brake – FLL guidelines and GRO (Green Roof Code) include requirements for fire breaks within the design of the green roof.
• Prevents debris from reaching gutters and can stop wind blown seeds from taking root.
• Some councils require it so its always best to check with your local council and/or planning board to see what you need and what you are allowed.

If you are looking to include a stone border in your green roof we have some quality Scottish pebbles for this purpose, and for roofs needing a stone border where there is no parapet or upstand, you might consider using our aluminium green roofing trims.

Green roof with a stone border

Green roof without a stone border

What is Sedum?

What is Sedum?

• Sedum is a low growing perennial plant that means you don't have to spend any time maintaining it.
• There is no need to mow sedum which makes it perfect for roofs as most are hard to get at.
• There are different types of sedums and our different systems have different sedum varieties in them too. This offers different colours, heights and leaf patterns. 

For our sedum types view these 2 pages

• Sedum Blanket Plus Types
• GrufeKit Sedum Types

Click here for our full range of green roofing products 

How will my Green Roof or GrufeKit be delivered?

How will my Green Roof or GrufeKit be delivered?

• Once you have ordered your Green Roof or GrufeKit, it will be delivered directly to site in time for you to install it.
• We will inform you on delivery dates once the order has been processed. 
  
• Delivery of sedum and wildlfower blankets will only be delivered on Tuesday through to Friday. We will work with you to arrange the best time for delivery. We do this to ensure the vegetation layer is in the best condition.
• The method of transport will depend on the size of the project. They are normally delivered on a pallet or in pallet loads and can sometimes arrive with different couriers on different days. We do this to make our prices the lowest we can so if you want everything to turn up at the same time please let us know before we quote you.
• It is advised that you have your fleece, drainage layer, substrate and trims ready for the sedum to be delivered and installed / planted on the same day as delivery. If you can't install it all in one day. Lay the sedum or wildflower mats out and keep them watered.
• Please advise us of any narrow roads or off loading problems that might occur. All deliveries will use large lorries unless specified. Sometimes large lorries can struggle getting to all locations. If your road is narrow or difficult to get to with a large lorry please advise us so we can arrange an alternative delivery vehicle for you. 
• Failure to do so may result in having to arrange a re-deliver which will cost or it being delivered further away from your property than is ideal.   

Click here for our full range of green roofing products 

What can I install my green roof on?

What can I install my green roof on?

• Green roofs can go on any waterproof roof but we recommend installing it on an EPDM system as this has the best life span of any type of roofing material and its also the greenest option available.
• Depending on how long your waterproofing materials have been on your roof its best to get it checked out. A green roof will last a long time and you are best making sure the roof is waterproof before the green roof is installed.
• Modular green roofing systems can also be used where maintenance of the roof or its waterproofing is likely. This is because the system can be lifted as it is made from interlocking tiles.
• Many companies will suggest using pond liners. There appeal is they are cheap but they also are very thin compared to an EPDM designed for roofing. They also don't have BBA certificates which is what ensures a product has been independently tested to last and work with a green roof. If you want more information on BBA certificates see our blog post here - BBA Blog Post on EPDM
• With any waterproof layer you will need to install a protective fleece first. This not only protects the waterproof layer but also keeps the substrate from washing away into the gutters.

View our online store for all our EPDM flat roofing products

Green roof installed with HERTALAN EPDM

Modular green roof system

Do you have to mow a green roof?

Do you have to mow a green roof?

• This depends on the plants used on the roof. We recommend using low maintenance options such as sedum or wildflowers for roofs as they are normally hard to reach.
• If you want to use grass use low growing grass that is can be bought from us. This doesn't grow as fast and won't need cutting as often.
• If you want a mown look on your roof you will likely be using it as a roof garden and this needs a different build up to the green roof
• If access is poor and you want a mown grass look you could use a robotic lawnmower to mow the grass for you.
• Grass can also be used to create a wild meadow which doesn't need much maintenance at all, you don't need to mow it but you can cut it back to encourage new growth. Over time as the nutrients wash out you will find sedums take well as they don't need much water or nutrients to survive.

View our online store for all our dedum and wildflower living roofing products

Mowing a Green Roof

Wildflower Green Roof

Sedum green roof

Bio-diverse green roof

Is my roof strong enough for a green roof?

Is my roof strong enough for a green roof?

• This is where its best to consult an architect, structural engineer or a building surveyor. If you go to one of these people if you can provide them with size of the span, the timbers used ie size & structural strength of them. They will normally be able to help for free or a small fee depending on the company or person.
• If you are in the design stage or on a new build you will likely already have one or more of these as a contact and they will be able to make sure the roof will take the weight. Most modern buildings will accept a green roof.
• All our products have saturated weights listed on the page and this is the weight that you need to make sure your roof will take this added weight.
• If you want to put a living roof on to your garden shed or any other small outbuilding that has been bought its best to contact the manufacturer to see what weight it will take.
• Contact us if you have any questions or need any advise on what you need to ask.
• For information on roof spans, joist sizes & weights that they can take please either use the TRADA span tables under section 7 for flat roofs or BS EN 1995 or contact a professional as mentioned above. 

View our online store for the saturated weights of our green roofing products

Can I cut GrufeTiles to make it fit my roof?

Can I cut GrufeTiles to make it fit my roof?

• Yes the modules can be cut with a hand saw or grinder. 

• The cut edge then needs to be faced into the rest of the green roof so that it’s supported by the next module.

View our online store for our GrufeKit living roof products

Do I need an aluminium green roof trim or GrufeGuard with my green roof?

Do I need an aluminium green roof trim or GrufeGuard with my green roof?

• Unless you have a built in kerb trim, parapet or upstand we recommend that you use the trims. They keep the green roof in the right place and also hide the drainage board / substrate or tiles. 

• If you use it with a stone boarder this can make the roof edge look much neater.
  
• If you want, we can offer alternative trims if the aluminium colour or design isn't to your requirements. 

View our online store for green roofing trims

Aluminium trim with a stone border

Green roof with an upstand and stone border

Green roof with PVC kerb trims on 3 sides and 

 aluminium green roof trim onto a PVC drip trim

Green Roofing Jargon Busting and FAQ's

Green Roofing Jargon Busting and FAQ's

We get many questions on Green Roofing and Living Roofs and here is a list we believe should simplify things for you.

What is the Difference between Extensive and Intensive Substrates?

Extensive is the most popular substrate / media mix for green roofs and consists of 80-90% of inorganic materials (crushed brick/pumice/L.I.C.A.) and 10-20% of organic materials (compost).

Intensive is the choice for roof gardens (See below for details on green roofs vs roof gardens).

The term Extensive means "covering or effecting a large area"

The extensive mixture is designed for low maintenance hence its popularity as most roofs are difficult to get regular access to for watering and weeding. The extensive roofs shouldn't need any watering during the year, however this will depend slightly on your planting choice and how hot and dry the summer becomes. Use common sense as you would with your garden at ground level, if it looks like it needs watering, water it. In some commercial applications contractors install a miniature roof at ground level with the exact same elements as the higher level roof to give an indication of how it is performing.

The intensive substrate mixture (circa 20-30% inorganic and 70-80% organic) is designed more for roof gardens when access is easy and you can take care of watering and maintenance as you would a normal lawn area.

Do I need a Drainage Board / Layer?

This depends on your roof. Many experienced green roofers and designers love to argue about the need of a drainage layer on a green roof, we tend to use the popular German FLL standards in the UK however the Austrian standards that do not favour drainage/water retaining boards are very successful also. (In later posts we will serialise these two respective standards).

If you are doing an extensive roof and the roof has a slight pitch on it, circa 1 to 40 fall ratio, then you can get away without a drainage layer. This is because drought tolerant plant species such as sedums do not like too much water or sitting in water. If you are doing a roof with a fall of 1 to 5 ratio you would need to consider some kind of retention board that prevents slippage.

You can also use the drainage layer as a water storage board too. There are various types of drainage layers from gravel to specialised plastic systems.

This is unless you are creating a wetland roof in which case you are looking for more water storage and this design should be carefully approached and even consider an irrigation system to maintain moisture.

Normally commercial living roofs require a water retention/drainage layer as part of the design.

What maintenance is needed?

This depends on the type of living roof you go with.

Drought tolerant species such as Sedum's are the lowest maintenance as they can survive in drought conditions. All they need is a light hand weed once a year for wind blown seeds if you are concerned with these.

Wildflower green roofs will require weeding once or twice a year and its best to cut them back at the end of autumn and remove the cuttings to retain their appearance.

To create biodiversity in a living roof its best to leave them to do there own thing.

You can create living roofs that use grass and depending on the finish you are looking for it can require mowing. If you want the green roof to be neatly mown make sure there is easy access or alternatively look at installing a robotic mower for the roof.

What is the lowest maintenance green roof?

Extensive roofs are the lowest maintenance, they can survive with little water and a low amount of input.

What should I put on my green roof?

This is totally up to you. The most popular are Sedums or Wildflowers. Our Sedum and Wildflower mat gives the best of both systems. If you are totally unsure contact us and we can advise further.

Is Sedum the best for a living roof?

This depends on what you want from a living roof. There are advantages to all types of living roofs.

How do I know if the roof is strong enough to have a green roof on?

This is a job for a professional. Your local building control officer should be able to handle this enquiry or an experienced architect, building surveyor or structural engineer will be able to inspect your roof to see what loading it can withstand.

We can advise on the weights of different systems when completely saturated with water (the worst case scenario).

If it is a new build project you will be able to make sure that the joists and structure are strong enough for whatever living roof you want.

If its an existing building you may be limited by the structure and joists as to the loading that you can put on the roof. If the structure or joists aren't strong enough you will be able to talk to an architect, building surveyor or structural engineer to see how you can upgrade the roof to be able to take the weight of the system you want.

Do I need planning permission?

This depends on your location and its always best to check with your local planning office.

Some districts require certain criteria to be met when a green roof is installed which usually involves a border of pebbles or gravel around the edge of the living roof. 

What are the benefits of a green roof?

There are many benefits of a green or living roof.

• Attracts wildlife by creating habitats.
• Wildflowers attract and help bees.
• They also catch heavy metal particles from industry.
• Provides extra insulation on the roof which keeps the building cooler in summer and can reduce heating costs in winter.
• Provides sound proofing.
• Can add value to your property by prolonging the life of the waterproofing membrane.
• Provides storm water retention – it helps release water slower than a normal roof. Helping to reduce flash flooding which is part of the governments S.U.D.S. (Sustainable Urban Drainage Systems)
• Plus it looks great!

How can I attract the most wildlife?

The best living roof for wildlife is to create as many micro habitats as possible.

This can include some of the following ideas:

·       Bee hives.

·       Logs and stone/bricks for critters to live under and around.

·       Bird feeders.

·       Wildflowers for the bees.

·       Shaded areas.

You can also create other types of habitats such as wetlands. This along with meadow areas have been reduced in the wild so creating these types of habitats are vital.

Can I make a wetland living roof?

Yes, its a new way of creating a living roof. There is more strain put on the roof so you need to contact an experienced architect, building surveyor or structural engineer to make sure that you can put that amount of load onto the roof. You also need to make sure the waterproofing materials are happy to sit in water. The waterproofing options we recommend are perfect for it.

What is the best waterproofing for green roofs?

We recommend using EPDM for green roofs. Our systems carry independent certification that the membranes and essentially the joints are suitable.  Many people recommend using pond liners and cheaper alternatives but a green roof is something that is built to last so why put something substandard on.  The easiest systems to fit and install are the UK Flat Roofing EPDM, HERTALAN EPDM and PRO-EPDM. We always recommend using the PRO-EPDM system as this is the highest quality and thickest EPDM on the market.

How easy is it to install a green roof?

Green roofs are reasonable easy to install. It is just a series of layers and the hardest part is getting the right information to achieve the right depths and of course getting all the layers onto the roof.

Which is easiest to fit a modular green roof or a living roof kit?

For someone with no experience the modular system is the easiest to fit. It is quick and easy to install however many people also enjoy taking their time and building the living roof as you would enjoy building your own garden.

How long will a green roof last?

With 70mm of extensive soil substrate there are enough nutrients in there to last circa 30 years.

What is the difference between a green roof and a roof garden?

A Green Roof is a roof that is normally not easily accessible and you wouldn't be using the space as a garden/terrace. Usually uses extensive systems.

A Roof Garden is an area that typically has green roofing materials on but is used as a garden / terrace. You need a different build up on the roof with deeper intensive substrates and different drainage layers etc. Contact us for a roof garden build up.

The extra substrate needed for a roof garden will mean you need to allow for much more weight on the roof. Professional help should be sought from building control, an experienced architect, building surveyor or a structural engineer to work out the weight that the roof can take or can be designed to take.

How much Substrate do I need?

Sedum's can survive in drought conditions and need the smallest amount of substrate on a green roof. We recommend using 70mm of extensive substrate or more.

Wildflowers need more substrate 100mm as a minimum ideally. The more substrate you have the more variety of wildflower you will have on your living roof.

To create further biodiversity in a green roof you can mound up the soil in areas to encourage burrowing invertebrates.

Adding logs and reclaimed bricks can also add to the biodiversity of your living roof.

When checking with a professional ask them about point loads to see if your roof is ok for adding a biodiversity living roof.

View our online store for all our green roofing products

Which EPDM system is the most cost effective and best?

Which EPDM system is the most cost effective and best?

A client, who was looking to replace his old flat roof, asked me what system would I use on my own roof and why.

I immediately replied HERTALAN or PRO-EPDM

He responded by asking why would you choose these systems as their BBA length is less than other cheaper brands. Meaning Firestone and ClassicBond.

It got me thinking about the BBA certificates and what they actually mean for the systems, after-all the BBA certificates are on the full system not just the EPDM. So if you use adhesives and accessories that aren't listed on the BBA certificate you may as well tear it up.

The BBA certificates for all systems are very precise in how the products should be fitted to achieve the service life.

They give accurate details on the following key areas

• How to install the EPDM membrane.
• Which adhesives to use and how much.
• Which accessories are included in the system.
• Who should install the system.

All systems require training from the manufacturer. If you don't have training and want to know how to install the systems yourself then videos and instruction are easy to find on the internet. Also all manufactures offer training days.

After this the systems vary massively.
Some manufacturers will supply their systems with
• Cheaper adhesives.
• Accessories that are non BBA approved.
• HERTALAN and PRO-EPDM don't have any cheaper non BBA options.

Here are my costings based on the original 5m x 6m enquiry and if you want to read more on how I get these figures I explain all the BBA documents further on in this post.

This table shows the Non BBA certified options and the prices. (ex vat)

So remember non of the above systems comply with the BBA testing standards and therefore  wouldn't be guaranteed to last the length quoted by the manufacturer in their BBA and would highly likely start giving problems within 10 years. The Hertalan 1.0mm has the best chance as its the same EPDM as the Hertalan 1.2mm and has the same adhesive.  However the other 2 systems just aren't going to last that long due to being installed to an uncertified method.  If suppliers tell you that you need less than is suggested within the manufacturers BBA certificate, then the system will ultimately fail. If it would work with less adhesives it would have been put through the tests with less adhesive.

In the table below we have all the options that are covered by the BBA certificate.

Following on from my pricing I explain below how I reached these conclusions and how to interpret the BBA certificates and what quantities of adhesives are actually required by the manufacturers.

Firestone RubberCover EPDM
One of the cheapest systems on the market for EPDM is Firestone RubberCover. If fitted correctly the product comes with BBA certification for 30 years on roofs up to 150m2 for domestic applications. Anything over 150m2 there is no BBA certification. The perceived low cost of this system stems from stockists/retailers selling the incorrect amounts of adhesives to make these systems appear cheap. To give an example of this, take the 10 litres of water based bonding adhesive, most online retailers suggest it will cover 50 sq.m however to comply with the BBA you need to use 1.3 litres per m2 (0.8 litres on the deck and 0.5 litres on the EPDM) which is a massive difference to the advertised 0.2 litres. Similarly if you just put it onto the deck and push the EPDM into it you need between 1.47 litres to 2.45 litres, depending on the condition of the surface, so even more expensive. So the correct amount of adhesive required, based on the manufacturers figures and to comply with their BBA certificate, will cost you between £9.75 + vat (for the 1.3 litre option) or £18.40 + vat (for the 2.45 litre option). So maybe this system isn't as cheap as has been suggested.

ClassicBond EPDM
Then we have ClassicBond which is a very similar system to Firestone RubberCover.  On the face of things a 35 year BBA. But again everyone sells the ClassicBond with a water based adhesive that hasn't been through the rigorous BBA product testing.
So if you want to comply with their BBA then you need to use contact adhesive and you need to mechanically fix the sheet around all perimeters and around any openings (skylights access hatches etc) with their RUSS strip. (This is a reinforced piece of EPDM with a pre attached splice tape that is screwed down and then you splice the back of the main sheet to the tape) So by the time you have added on the Russ strip and the mechanical fixings plus the contact adhesive you end up a long way from the price quoted by some retailers with little or no flat roof experience. (ClassicBond is also sold under the name Carlisle Syntec)

Duoply EPDM
DuoPly is a Fleece backed version of ClassicBond and again on the internet is advertised with a water based adhesive (WBA) which isn't BBA certified. You have to use a polyurethane (PU) adhesive and the RUSS strip system at perimeters and skylights etc. (This is also sold under RubberBond)

HERTALAN and PRO-EPDM
HERTALAN and PRO-EPDM systems have a 25 year BBA and don't have any cheaper options for installation. So prices that are advertised on the internet are as they should be. This is where these systems start to prove how cost effective they are and look better than originally thought.

RESITRIX SKW & SR
RESITRIX SKW and SR both carry a 30 year BBA and the amount of primer that is advertised (250g per m2 when applied with a roller or 120g per m2 if applied with spray canister) is as per manufacturers guidelines and that which went through the BBA testing.

So now I have explained the most popular EPDM systems and what must be done to comply with their BBA certificates and the costings on my clients original enquiry which was his 5m x 6m double garage roof, you can clearly see to achieve a roof to a BBA certified standard its very different to what is advertised by many of the stockists and dealers and you can see why I immediately said HERTALAN or PRO-EPDM as my preferred systems.

When it comes to installation HERTALAN and PRO-EPDM are uncomplicated systems that make them fast and easy to install and therefore even more cost effective due to lower labour costs? So in terms of productivity and material costs to get a BBA certified roofing system HERTALAN EPDM and PRO-EPDM are certainly in my opinion the best option.

For anyone who is interested in seeing the BBA certificates I have included a link below.

All prices are from internet retailers and details are available on request.

References

BBA – HERTALAN and PRO-EPDM 
BBA – RESITRIX SKW
BBA – RESITRIX SR
BBA – ClassicBond 
BBA – DuoPly
BBA – Firestone