Most building product manufacturers hand specifiers a datasheet and hope for the best. Then they wonder why the wrong product gets written into the tender, why contractors ring asking questions that should have been answered in the specification, or why their system loses out to a competitor who made it simpler to specify correctly. The truth is that construction specifications are written under time pressure by people juggling dozens of products across multiple projects. If you make their job harder, you will not get specified.
We have worked with manufacturers who treat specification support as an afterthought, and others who recognise it as the difference between being named in the tender documents or listed as "or equivalent". The gap is not usually product quality. It is clarity. A well-written specification entry does the specifier's work for them: it describes what you supply, how it performs, where it fits, and what standards it meets. This post walks through five practical steps to write specification clauses that get your product chosen and specified accurately.
Before you write anything, it helps to understand how specifications are used. Architects, engineers, and specialist consultants write specifications to tell contractors exactly what to install. These documents sit alongside drawings and form part of the contract. They define materials, products, performance criteria, installation methods, and testing requirements. If something goes wrong on site, the specification is what gets checked.
Most UK projects use NBS, the National Building Specification system, which provides a library of standardised clauses that specifiers adapt to each project. Specifiers search for a product type, select a clause template, then edit it to describe the products they want. If your product is not easy to describe within that structure, or if the information they need is buried in a 40-page brochure, they will specify what is easier. Your job is to give them the clause, ready to drop in.
Every specification entry needs a short, accurate product description that identifies what you supply. This is not marketing copy. It is a contract description. Be specific about what the product is, what it does, and any key characteristics that distinguish it from alternatives.
Good example: "Insulated render board: rigid polyisocyanurate core faced both sides with glass fibre tissue, factory-bonded to 6 mm cement particle board. Thermal conductivity 0.022 W/mK. Available in thicknesses 60 mm to 120 mm."
Weak example: "High-performance insulated board system offering exceptional thermal efficiency for a wide range of applications."
Include your product name and code, but do not rely on them alone. Specifiers often write performance-based specifications that allow contractors to propose alternatives, so the functional description matters more than the brand. If you want to be named specifically (a proprietary specification), make sure the performance criteria are tight enough that only your product qualifies, and be prepared to justify why equivalents are not acceptable.
Specifiers need to demonstrate compliance with Building Regulations, project performance targets, and client requirements. Your specification entry should state the relevant standards, test methods, and certification schemes your product meets. Be precise. "Meets all relevant standards" tells them nothing. "Tested to BS 476-7:1997, Class 1 surface spread of flame" gives them what they need.
List the key performance metrics that matter for your product type:
If your product has third-party certification (BBA, LABC, BRE, Agrément), include the certificate number. If it has been independently tested, cite the test house and report reference. Specifiers trust verified data. They are wary of in-house claims.
One of the most common reasons products get mis-specified is poor information about what they work with. Your specification entry should describe interfaces with adjacent materials, compatible substrates, fixing methods, and any products that must not be used alongside yours.
If your system only works with specific adhesives, primers, or fixings, name them. If it requires a particular substrate preparation or damp-proof membrane, state that. If there are common errors (wrong fixings, incompatible sealants, missing expansion joints), use the specification to close them down. This is especially important for systems like external wall insulation, waterproofing, or façade assemblies where multiple trades and products meet.
Also consider sequence and coordination. Does your product need to go in before or after services are installed? Does it require temporary support? Does it need protection during follow-on trades? These notes help the contractor read the specification and understand dependencies, which reduces site queries and variation costs later.
If you want your clause to be used, format it the way specifiers expect. NBS clauses follow a consistent structure, and most project specifications mirror it even when they are not using the NBS library directly. Organise your specification entry into clear sections:
Keep the language clear and imperative. "Fix boards vertically with staggered joints" is better than "Boards should ideally be fixed in a vertical orientation with joints staggered where possible." Specifications are instructions, not suggestions.
Offer the clause as an editable document, not a PDF. Specifiers will not retype it. Make it available on your website as a downloadable Word file or plain text block. Some manufacturers include NBS-ready clauses in their technical literature or on product pages. Others provide them on request. Either way, make it obvious they exist. This kind of specification support fits naturally alongside technical brochure design that prioritises usability for professionals who need data quickly.
Writing good specification clauses is not a one-off task. Products change, standards update, and new applications emerge. Treat your specification library the same way you treat datasheets: as living documents that need regular review.
If you run a CPD programme, use it to explain how your products should be specified and why. If you are rebuilding your website, make specification clauses easy to find on product pages. If you publish technical guides, include sample clauses that cover common project scenarios. Specifiers will use what is easiest to find and simplest to adapt. The more you reduce friction, the more often your products get named.
This approach works best when your specification content, technical documentation, and digital presence all support each other. A clear specification clause is only useful if specifiers can find it when they need it, which is why building a structured product library matters just as much as the content itself.
Good specification writing is not glamorous, but it is one of the most direct ways to influence what gets built. Most manufacturers under-invest in it, which means the effort you put in will stand out. If you make it easier for specifiers to choose and describe your product accurately, you will win more projects, reduce site errors, and build stronger relationships with the consultants who control what gets specified.
If you need help writing specification content, structuring product data, or making technical information easier to use, get in touch. We work with building product manufacturers to close the gap between what they make and how clearly they communicate it.
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