Fire Stopping in Welwyn
Fire stopping for Welwyn, from a contractor working since 2005. Fully insured, with a 12-month guarantee.
- Non-fire-rated filler around services
- Snag lists that include open service penetrations
- Old intumescent sealant that has split away
Need fire stopping in Welwyn?
Share the site address and what’s failing, and we’ll reply with a fixed quote or arrange a visit.
From enquiry to sign-off
Diagnose, treat, sign off: that’s the shape of every visit. We inspect the joints and confirm what’s in scope, then the work is carried out to the specified product and detail, and we finish with a walk round so the work can be signed off. For a site in Welwyn, we plan so the whole job is done in one go where possible. Clear photographs and measurements help us bring the right products.
- First we go through the drawings, schedule or specification for the seals and ask about anything unclear.
- On site, each opening is checked against the tested detail it is meant to follow.
- Anything that doesn’t belong in the opening, such as expanding foam or general-purpose filler, is removed.
- Mineral wool or other backing goes in wherever the detail asks.
- Fire-rated or intumescent sealant is gunned in to the specified depth, then tooled.
- If an opening needs something other than sealant, we tell you instead of improvising.
Before we start on site
- Send your site hours and access windows
- Send asbestos survey details if the building is pre-2000
- Explain the parking and delivery arrangements
Getting a fixed quote
Every quote starts with the facts: what’s there, how much of it, how we reach it and what’s specified. Share whatever details you have and we will fill any gaps with a visit.
Read more
About our fire stopping in Welwyn
Every service that crosses a compartment wall or floor leaves an opening, and that opening needs sealing to hold back fire and smoke. Our job is fitting fire-rated and intumescent sealant at those service penetrations, and along linear gaps, where it is the specified product. Each seal follows the manufacturer’s tested detail, not a rule of thumb. We work on linear gaps at wall heads, service gaps in risers and cable penetrations, and the failures we are asked to look at most are non-fire-rated filler around services and fire sealant pulled out of the opening. Sealant contractors, mastic applicators, sealant specialists: whatever the job title on the order, the work in Welwyn is the same: failed joints cut out, faces prepared and the right sealant laid to the right depth.
Fire-rated sealing in a place like Welwyn is typically a single building at a time. Send the specification, drawings or photos of the openings and we will quote to suit.
We sign every job off with a 12-month guarantee. The promise is simple: if our work fails within that year, we put it right.
- Location
- Welwyn (AL6)
- Region
- Hertfordshire
- Guarantee
- A 12-month guarantee
- Price
- A fixed quote before we start
- Call
- 01277 525 020
- Last updated
- 3 November 2026
Other services in Welwyn
For managing agents and facilities managers
As a CHAS accredited contractor and Constructionline member, we make supplier vetting simple. We’re fully insured, and our insurance certificate can go with the quote.
If you look after buildings for someone else, you need clear quotes and clear reporting. We quote a fixed sum, confirm the scope and walk the finished work with you or your representative, plus a 12-month guarantee.
How the job changes by surface
Risers and ceiling voids
Risers and ceiling voids hold most of a building’s service penetrations. Access to these areas is planned with you in advance.
Cables and cable bundles
Cable penetrations are frequently sealed with fire-rated sealant where the detail allows. Bundle size, cable type and the space between cables all matter and we work within those limits.
When it isn’t the sealant
A proper diagnosis includes knowing what sealant can’t do. You’ll hear from us if the cause turns out to be one of these:
- Reviewing a building’s overall fire safety
- Large openings beyond what any sealant detail covers
- Construction that lacks the fire resistance the seal relies on
If in doubt, call the office on 01277 525 020 or email us and we will say what we think.
Joints and surfaces we work on
- Service gaps in risers
- Cable penetrations
- Small duct penetrations where the tested detail allows
- Pipe penetrations
- Joints between fire-resisting walls and floors
- Linear gaps at wall heads
Maintenance after handover
Regular inspection catches problems early. In particular:
- Flag new cables with no seal around them
- Record which product was used where
- Check risers and ceiling voids after each round of works
- Check with the data sheet before painting over fire sealant
Keep the product data and installation details with the building’s fire safety information. It makes later repairs much easier to match.
Regular walk-rounds of service areas are worth the time. A cracked or disturbed seal found early is a small job.
Should maintenance staff do it?
Certain joints really need a specialist: fire-rated seals that must follow a tested detail, trafficked floor joints and external movement joints among them. Getting these wrong typically costs more in the end than doing them right.
There’s also the paperwork. Main contractors and clients often ask for CSCS cards, RAMS and insurance details, and our CSCS-carded applicators are used to working under those rules.
Questions about Welwyn
Can work at a site such as University of Hertfordshire fit around teaching?
Yes. We plan campus work around teaching, exams and residence turnarounds. Any paperwork you need, from RAMS to our insurance certificate and CSCS details, is confirmed with the quote.
Is Welwyn off your patch?
No. Places such as Welwyn are covered as much as the big towns. We work across Greater London and the South East. We plan jobs in smaller places so return trips are kept to a minimum.
What does an EI 60 rating mean?
In short, BS EN 1366-3 and 1366-4 are the fire tests and BS EN 13501-2 is how results are classified. An EI 60 seal kept its integrity and insulation for 60 minutes as tested and the installation has to match the test.
Will you just go over the old sealant?
No, never. Sealing over old material is one of the classic causes of early joint failure, so everything comes out first.
Is the BS 476 change in 2029 relevant to fire stopping?
It mainly affects England, where Approved Document B is dropping its BS 476 references from 2 September 2029. Classification to BS EN 13501-2 becomes the expected evidence, subject to transitional arrangements. Scotland follows its own Technical Handbook, including clause 2.1.14 on service penetrations.
Do you hold third-party fire-stopping installer certification?
No. We don’t hold a third-party fire-stopping installer certificate. We are CHAS accredited and a Constructionline member, and our applicators are CSCS-carded. Where a client or main contractor requires a scheme member, we will say so right away rather than waste your time.
Do you certify or sign off fire stopping?
No. We don’t certify or sign off fire stopping, and we hold no third-party fire-stopping installer certificate. We work to the specification and the manufacturer’s installation guidance, and any records you need can be confirmed with the quote.
Fire stopping in Welwyn: the local picture
Approved Document B is the English guidance that covers fire stopping around openings and penetrations. The national BS 476 classes are due to drop out of it from 2 September 2029, leaving the European BS EN 13501-2 route, subject to transitional arrangements. Our part stays the same: the specified product, installed to its tested detail. Central London is about 23 miles from Welwyn. Business park offices in the commuter belt are refitted as tenants change, and each fit-out adds services through compartment walls; the gaps need the specified seal.
Large healthcare estates like Queen Elizabeth II Hospital, 3.5 miles to the south of Welwyn, change their services often, so penetration seals are worth checking after M&E work. At a university such as University of Hertfordshire, 5 miles to the south of Welwyn, labs, lecture blocks and residences are re-serviced often, so penetration seals are best checked after M&E work. Tenant changes at centres like Howard Centre (to the south of Welwyn) often mean new services through walls between units.
Welwyn is about 2 miles north-west of Welwyn Garden City, in Hertfordshire. We send applicators to Welwyn for service penetrations, handled exactly as we handle every other area. Welwyn is one of 371 places we cover in Hertfordshire. We also cover London, some 23 miles away.
Commercial sites across AL6 are covered for service penetrations. For a building on High Street, London Road and Mimram Place or nearby, send details and we will quote for service penetrations. Just outside Welwyn, we also work in Monkswood (1 mile south-east), Ayot St Peter (1 mile south-west), Ayot Green (1 mile south-west), Pottersheath (2 miles north) and Codicote (2 miles north-west). A short drive away, we cover Watford (14 miles south-west), Hemel Hempstead (12 miles south-west), Stevenage (6 miles north), St Albans (7 miles south-west), Harpenden (6 miles west) and Hitchin (9 miles north).
What’s near Welwyn
Locally, jobs take us to sites close to Stable Door pub, Danesbury Park and Homerswood Primary and Nursery School. For rail, the closest station is Welwyn North station, about 1.1 miles south-east. Well-known places in the area include Queen Elizabeth II Hospital (3.5 miles south) and Datchworth Museum (2.7 miles north-east). Open spaces near Welwyn include Mardley Heath.