When you appoint a ground gas verification company, you are buying one thing: an independent, insured opinion that the protection under your slab was installed properly. The name on the quote is not always the person who turns up to give it.
More verification work is being passed to self-employed subcontractors, booked by the day and sent to site under the appointed firm's name. Plenty of them are good at the job. The problem is what the arrangement can hide: who else that person works for, and whose insurance stands behind what they sign.
Independence is what you are paying for
The guidance is consistent on this. CIRIA C735 and BS 8485 both promote independent verification, and installers cannot verify their own work. Councils in Yorkshire and Lincolnshire go further and ask the verification plan to include a "clear demonstration of the independence of the person carrying out the verification".
The CL:AIRE accreditation scheme for verifiers puts the duty on the individual. Accredited verifiers must not let conflicts of interest influence their judgement, and must tell all relevant parties about any conflict.
Notice the word person. Independence is tested at the level of whoever is on site with the camera, not the logo on the report.
The conflict you can't see
A self-employed verifier rarely works for one company. They may inspect your membrane on Monday, then spend the rest of the week working with an installer or supplier whose system competes with the one under your slab. On another site, they may be working for the very installer whose work they are checking on yours.
None of that makes an inspection wrong. It does mean someone with a commercial interest in the outcome is deciding whether your installation passes, and nobody told you.
It also breaks the chain of disclosure. A firm that doesn't know who else its subcontractor works for cannot declare a conflict to you or to the council. If a defect surfaces later, that undeclared link is the first thing a regulator, an insurer or a buyer's solicitor will ask about.
The insurance gap
A verification report is professional advice. If it is wrong, the claim lands on professional indemnity (PI) insurance, often years after the slab was poured.
With a directly employed verifier the position is simple: the firm's policy covers its own staff. With a subcontractor it depends. Insurers generally expect a self-employed subcontractor working under their own direction to carry their own cover. Whether the appointing firm's policy also responds turns on its wording and on what the firm has told its insurer about using subcontractors.
Two things make this worse for ground gas work:
- PI is "claims made". The policy that responds is the one in force when the claim is made, not when the inspection happened. A subcontractor who has moved on or let their cover lapse leaves nothing behind.
- Limits may not match. If the subcontractor's limit is lower than the appointing firm's, the difference is exposed.
Where the arrangement is informal, with a day rate, no written contract and no insurance check, nobody may have asked these questions at all. The developer finds out only when something goes wrong.
Five questions to ask before you appoint
- Who will be on my site? Ask for a name, and whether they are employed by you or subcontracted.
- What are their qualifications? Ask for training, experience and any CL:AIRE accreditation, in writing.
- Who else do they work for? Ask for a written declaration of any link to the installer, the membrane supplier or a competing system.
- Whose insurance covers the inspection and the report? Ask for the PI certificate and, if the verifier is subcontracted, theirs as well.
- Who signs the report? Ask whether that person was on site, and how they checked the work of anyone who was.
A good verifier will answer all five in one email. Ask for the answers to go into the verification plan, where the council can see them too.
How we do it
At FS Verification, the person who inspects your site is directly employed by us and covered by our own professional indemnity insurance. They do not install or sell gas protection systems, for us or for anyone else. You get the same person from the verification plan to the final report, and their name and qualifications are in the plan before work starts.
If you have a ground gas condition on your decision notice, send it over and ask us the five questions. We'll answer them before we quote.
07813 788537 · info@fsverification.com
Probably the smoothest and most cost-effective verification.