What a BalcoDeck® Certificate of Compliance Actually Contains - and Who it Protects

When architects and developers specify BalcoDeck® for a roof terrace installation, the Certificate of Compliance is the document that closes the loop. It is what building control asks for at sign-off. It is what an insurer may request when a claim is made. It is what a valuer or lender may want to see at re-mortgage. And yet most design teams have only a vague sense of what the certificate actually contains - until they need it.

Our article explains the document in full: what it confirms, what it covers, and who it protects.

What the certificate confirms

The BalcoDeck® Certificate of Compliance is issued by Balconette following a completed installation. It confirms two distinct things: structural performance and membrane integrity.

On the structural side, the certificate confirms that the installed system has been designed and manufactured to resist the wind loads and lateral forces acting on the balustrade, in accordance with BS EN 1991-1-4 and BS 6180, without any fixing penetrating the waterproof membrane or the structural substrate beneath it. The base moment calculations, platform geometry and load distribution methodology are all referenced in the supporting documentation.

On the waterproofing side, the certificate confirms that the membrane has not been penetrated during installation. This is not simply a statement - it is backed by a pre-installation survey record, installation methodology documentation, and a post-installation check confirming membrane continuity. The certificate therefore provides documentary evidence of membrane integrity at the point of installation, which is something a conventional penetrative installation cannot provide.

What the certificate means for architects

For the specifying architect, the certificate performs a specific function in the PI chain. It establishes that a system with a known structural performance record was installed in accordance with its design intent, and that the waterproofing layer was preserved in the process.

This matters because one of the most common routes to an architect PI claim on a roof terrace project is a leak that develops years after completion, where the cause is traced to a fixing penetration that was signed off at practical completion but was never adequately detailed. The certificate does not eliminate all risk - but it changes the evidential position substantially. There is a document confirming that at the point of installation, the membrane was intact and the structural system was compliant.

Under the Building Safety Act 2022, the Principal Designer now carries a duty to maintain the golden thread of documentation from design intent through to as-built. The BalcoDeck® certificate, alongside the pre-installation survey and installation records, forms part of that thread. It is one of the few pieces of documentation on a roof terrace project that can confirm both structural compliance and waterproofing integrity in a single document.

What the certificate means for developers

For the developer, the certificate supports the warranty position in two ways. First, it provides evidence that the waterproof membrane has not been penetrated by the balustrade or decking installation, which is the most common basis on which membrane manufacturers void their warranties. A membrane warranty that is kept intact has real commercial value - particularly on a development where the roof terrace is positioned as a premium amenity feature.

Second, the certificate provides a basis for defending against latent defect claims. If a claim is made in year eight that the roof terrace is leaking, and the cause is alleged to be the balustrade installation, the certificate provides contemporaneous evidence of the installation method and its compliance. This does not mean claims will not arise - but it means the developer is not in the position of having to prove a negative.

What the certificate means at building control sign-off

Building control officers are increasingly asking, on roof terrace projects above occupied space, how the balustrade loads have been transferred to the building without compromising the waterproofing system. This is a legitimate technical question and one that conventional penetrative systems cannot answer cleanly, because the answer requires the contractor, the membrane installer and the structural engineer all to be in agreement about a detail that was designed at interfaces between their scopes.

The BalcoDeck® certificate answers this question directly. It confirms the load transfer methodology, the BS EN compliance basis, and the installation record. For most building control officers, this is sufficient to close the structural and waterproofing queries in a single document submission.

What the certificate means for lenders and valuers

This is a less discussed but increasingly relevant dimension. Mortgage lenders and RICS valuers are beginning to ask, on properties with roof terraces, whether there is documentary evidence that the balustrade installation has not compromised the waterproofing system. The BalcoDeck® certificate provides exactly that evidence, in a format that is readable by a non-specialist audience and credible to an insurance or valuation professional.

As roof terraces become more common in residential development, the expectation that there is documentation confirming the integrity of the waterproofing under the terrace build-up is likely to become more standard. The certificate positions the property well for that scrutiny.

What the certificate does not cover

It is important to be clear about the boundaries of the certificate. It confirms the installation as completed at a specific point in time. It does not guarantee the long-term performance of the membrane against all future risks, nor does it cover modifications made after installation. It is a point-in-time compliance document, not a perpetual warranty. And like all structural compliance documentation, its value depends on the records being kept and made available when needed - which is where the golden thread obligation under the Building Safety Act becomes relevant.

The certificate is most valuable when it is part of a complete set of documentation: the pre-installation survey, the installation methodology record, the structural calculation pack, and the post-installation check. Together, these constitute the evidence base that protects all parties in the event of a future question about the installation.

For specifiers who have not previously requested this documentation as a contractual deliverable, it is worth considering whether the Certificate of Compliance and its supporting records should be included in the employer's requirements or specification as a named deliverable at practical completion.