Pitched Roof Newbuild Product Selector
IntroductionKnowing what flat roof covering to choose when designing a new building or extension can be challenging without in-depth knowledge of what's on the market.
Taking advice often brings into the question the motivations of the advisor - what are they selling?
Architects often have a broad unbiased knowledge of the systems available but specifying a covering for a very specific purpose can present a huge list of do's and don'ts. If your architect isn't completely up to date with what's available, or hasn't personally been aware of some of the drawbacks of specifying the wrong material, problems can present themselves during the build process.
Any good architect will approach this with an open mind and discuss the merits of product selection with a professional roofing contractor until they are sure that they have specified the right system for the right job to ensure your budget stays on track.
Some systems will work well with complicated detail on the roof, some not so well.
EPDM is a great one-sheet system and will perform as well as any other product for big flat areas without the requirement for a huge budget - but we wouldn't specify this for a big L-shaped flat roof extension with parapet walls and roof lanterns. Every change in direction or corner detail needs an EPDM patch applying, there are much better systems for a roof of this type.
GRP or Fibreglass is a great looking system and extremely hard wearing, but is it worth the extra cost and weight if the roof isn't seen and won't have any foot traffic on it?
Your Product ChoicesSo the choices to consider when specifying a flat roof on your project are going to include:
- Is the roof part of the aesthetic design of the building?
- How important are it's looks?
- How will it look in 10-20 years?
- Are you planning to put anything on the roof?
- Is it a Terrace?
- Are you putting a living roof onto it?
- Does it need a non-slip walkway to access plant or other areas of the building?
- How much detail is there?
- Lanterns, skylights, parapet walls, pipe penetrations, solar panels, steps, box gutters?
- Some systems will work better than others.
- How will the roof stand up to burning embers from nearby buildings that could potentially catch fire?
- How important are the visuals of the roofline?
- Does the trim colour need to match new windows or decorative guttering?
- What are the thermal requirements of the building?
- Some systems will be more efficient when laid over a slab of PIR insulation.
- Most systems carry a guarantee which will be covered by a manufacturer and the installer.
- If you're worried about either of those two going out of business, you may need a warranty which is more like an insurance-backed guarantee.
- If the companies are no longer trading, an insurance company will send out a contractor to repair the work under a warranty agreement.
- Both need to be agreed before the job commences and can't usually be arranged after the work has been completed.
- If you're building a newbuild or self build, do you need to refinance or sell the building?
- Many mortgage lenders will insist on an insurance backed guarantee or warranty at the point of sale - You cannot arrange this afterwards.
- How long do you need the roof to last?
- Is your building temporary? Are you planning to put a 2nd story onto an extension in the future?
- Do you have a short term lease?
- How old are you?!
- Don't forget flat roofs become heavier when covered in slabs, decking or a green roof.
- Add some snow to that and this is a serious consideration if you have other restrictions with the roof structure.
- How much do you want to spend on your new roof?
- How do the suitable systems compare is the upfront cost outweighed by the lifespan or the value it will add to the building?
- As little as possible? - There will be a solution for this depending on the other considerations such as the level of complexity.
- How easy is it to access your new roof?
- All roofs will need checking and debris clearing once a year at least.
- If its not easy to access, go for one that is more robust and needs minimal maintenance.
- Is your contractor fully trained & accredited and has a long track record of successful projects?
- Is the system you have selected BBA Approved?
- Would you use a torch-on felt system on a timber framed newbuild?
- Is the roof in a sensitive area where strong odours from a GRP or liquid applied system would cause upset in a restaurant, hospital or carehome?
- Can you be sure you are going to get a fall on your roof - some will stand underwater better than others.
- Timber framed buildings can shrink at a rate of 50mm per floor. Will this affect your roof covering?
There's a lot to consider when designing this part of your building, get it right to start with and have no regrets later.
Call us on 01664 431370 and get a free 15 minute consultation with one of our technical experts to ensure you specify the right material for your project.
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