11 Tips For Writing Successful Roofing Specifications

The purpose of a well-written specification is to ensure that the design criteria, product selection and installation of a flat roof system combine highest performance with the best value. The quality of tenders returned and the quality of the installation at the end of the process will reflect the quality of the specification: care and insight is required. At IKO, we’re on the receiving end of a lot of specifications and we are happy to share our 11-point guide to successful spec writing.

11 Tips For Writing Successful Specifications

1. New Build or Refurbishment?

Start with the obvious.  A new build project needs a very different approach to a refurbishment project, so it’s best to be clear right at the beginning.

A new build roof system will need to conform with all current legislation. Check Building Regulations requirements but don’t forget also to include the health and safety considerations and always ensure the installation procedure is in line with good practice.

One of the first questions to consider at this stage is the anticipated lifespan of the building: the roof should be designed to last the same length of time.

Refurbishment projects need a more detailed approach.  Building regulations and health and safety are still important, of course, but the specification must make clear the condition of the existing roof and a comprehensive written condition survey including core samples and photography is a must.

Information on whether the roof meets current standards should be supplied as should details of any changes that will need to be made during the refurbishment, such as falls drainage or thermal performance.  Be specific to ensure all these issues are addressed and priced in the tender.

Skimping on a survey can lead to costly mistakes so it really is worth taking the time for a detailed investigation and report.  Potential savings may also be revealed during this process: for example parts of the roof may still be in good condition or the waterproofing may not need to be stripped and installed again in its entirety.

2. Selecting the Tender List

How you set about deciding who receives your specification will have an impact on the quality of the installation, so take care to include quality assessment measures to ensure the recipients are up to scratch. If possible, establish set criteria at the start, enabling you to rank tenders dispassionately and fairly.

If you are using a portal or framework platform, the respondents may still have to go through the PQQ process, but the tender will be open to anyone to view – reducing your control over the types of companies who respond and also allowing competitors to see who they are up against.

You can avoid some quality issues by including caveats in the specification. These could include: named products (if alternatives are suggested you need to be confident that they are of equal quality); approved contractor requirements and details of specialist works to be included.

If still in doubt, ask to see case studies of previous contracts which will give you an idea of the type of experience the company has.  You may also consider its record with regard to HSE, Construction (Design and Management) Regulations and its financial performance.

3. Selecting Contractors

While you are considering all of the work that will be required, it’s important to remember that the works will have to be carried out by someone.  This could be a single contractor or a number of specialist contractors and sub-contractors.

Consider whether you need to approach particular specialists or if the tender can be open to anyone.  Remember that even if you have a list of four or five preferred suppliers whose quality you trust,  they may not be available when you need them and widening the pool of trusted contractors is always advisable.

Where subcontractors will be part of the team your quality assessment process needs to consider them as well.  Making sure that these companies are qualified and approved by the relevant trade bodies can provide that assurance.

Any roof installation means working at height, so Health and Safety qualifications and practices will be the first and foremost considerations.

4. Setting a Budget Expectation

Of course you want the best quality result for the lowest possible cost, but if you have any set budget restraints it’s best to say so – it is simply a waste of everyone’s time if the respondent cannot realistically come close to a proposed budget and you need to know if such a budget is unachievable.  Also make clear if you are asking for an explanation of ROI or if you are simply asking for a cost.

Spell out what penalties – if there are any – will be incurred for missed deadlines and bear in mind that if such penalties are included then location and weather will be additional factors to be considered.

John Ruskin said it best:

“It’s unwise to pay too much, but it’s worse to pay too little.  When you pay too much, you lose a little money – that’s all. When you pay too little you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do.”

5. Considering Durability

Be as clear as you can about how you need the roof to perform and what are the most important characteristics – this will allow your respondent to select the right build-up or roofing system to meet the individual performance requirements.

Outline what will be the most important functions beyond basic waterproofing, such as:

    • Durability – how long should the roof be expected to last?
    • Low maintenance?
    • How much traffic? (low, medium or high level?)
    • Environmentally friendly? Any specific performance you’re looking for?
    • Will it require edge protection?
    • Is there access for maintenance?
    • Is there any plant to consider?
    • Will it need to support or integrate with solar thermal or solar PV systems?
    • What type of guarantee are you looking for?
6. Aesthetics

While practically speaking the main function of a roof is to provide shelter and possibly warmth to occupants and amenities, the roof can provide definition to the building. There are a number of considerations to ensure that a client receives an aesthetically pleasing roof that both meets the requirements of Build Regulations and enhances that character of the building as a whole.

Will the roof be required to sit sympathetically within its surroundings and if so does this mean simply colour match or material cohesion as well? If consistency in materials is required, what does this mean for maintenance further down the track or how will this affect the performance requirements of the building.

What plant facilities are required on the roof scape and will this need to be hidden from plain sight or blended into its surroundings.

7. Guarantee Options

Obviously you will be asking for guarantees, but bear in mind that the type of guarantee can differ depending on the type of construction build up and the purpose of the building. Essentially you are providing peace-of-mind but that comes at a cost and so don’t ask for a more onerous guarantee than you need.

The IKO Single Point Guarantee covers everything from materials to workmanship and is the most comprehensive guarantee that IKO offers. However, this may not be required and a simplified guarantee covering just materials may be sufficient. It’s important to get the cover you need for the specific project.

The length of the guarantee is also a consideration and can be determined by the materials used, the systems specified or the preferred type of waterproofing.

8. Selecting the Manufacturers

A good contractor and a good installation will ultimately only be as good as the quality of products and systems that they are working with.

Selecting a legitimate roofing manufacturer for felt, membrane materials, single-ply, hot melt, mastic asphalt or liquid will not only ensure the products are good quality but also determine the level of pre and after-sales service provided.

Take into consideration where the manufacturer is based.  If the company is UK-based are the products manufactured in the UK or sourced from Europe or further afield. This will determine what accreditation the products will have and be reflected in the product quality.

Can the manufacturer back up its product performance claims with legitimate third-party accreditations and is there further proof in the form of BBA certification, DoPs, data sheets and case studies?

What environmental credentials are offered and does the manufacturer have a good safety record?

Finally, the products may need to be compatible with those supplied by other manufacturers. Is it easier to source everything from a single supplier rather than worrying about the consequences of compatibility issues? Working with a supplier that can assist with design and build up can eliminate much of this stress.

9. Environmental Impact of Specification

Naturally you will want the project to have minimal environmental impact, but what does this mean for this project?

The complexity – and cost – of different approaches can vary enormously.  Would you like to see a green roof or a design that incorporates solar systems?  Will you be looking for evidence that the suppliers take a positive approach to packaging design and the recycling of waste / unused product? You will also want to know what steps will be taken to minimise CO2 emissions from transport: this last point can be addressed by considering where the products are manufactured and the distance they need to travel to get to site.

You can choose to be very specific about your requirements – such as asking for ISO certification or specific waste reduction measures –  or invite suppliers to volunteer their own solutions, but guidance will help to ensure you are giving a level playing field when it comes to comparing cost.

10. Health and Safety Requirements for the Products

Working at height is always a risky operation and health and safety procedures must be followed to the letter.  However, the health and safety characteristics of the products too should be considered at the initial stages of the project, particularly with regard to issues around fire.

Always check that products have the standard accreditations and test results as well as any additional performance claims.  Make absolutely sure that the required fire safety tests have been carried out and opt for a flame-free application if at all possible: remember that at least one fire a day is caused by hot works on commercial or industrial properties.

Make sure that contractors have not only used the products before but are familiar also with the tools and processes involved – check also that the components used to make up the roof system have been used in that precise combination in other projects and ask for evidence.

Ensure products are CE marked and outline required safety procedures, paying particular regard to obvious potential hazards such as fragile roofing decks or rooflights.

It is always important to remember who will be liable for any injuries on site, with the specifier’s contribution being to reduce risk right at the start of the project, through considered specification and through recommending schemes such as Safe2Torch which can save time, money and reduce risks before work on site starts.

11. Can it be Done?

Once you have worked through all of the above, take the time to reflect on whether the specification is realistically achievable within the time, resource and budget available – it’s better to make changes at this stage than to risk having no responses to the tender invitation or encouraging contractors to put in unrealistic bids.

The most cost effective time to change any elements of a specification is right at the start.  The longer it is left or the more that needs to change further into the project, the larger the implications.  It really is important to get it right first time.

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