Fire stopping in Harmer Green
Fire-rated and intumescent sealing of service penetrations and linear gaps in Harmer Green and across Hertfordshire. CHAS accredited and fully insured, with a 12-month guarantee.
- Unsealed openings around new pipes and cables
- Builders’ foam or ordinary silicone in compartment walls
- Snag lists that include open service penetrations
Fire stopping in Harmer Green
Photos, a specification or a quick description of the joints is enough to start a fixed quote.
How we handle fire stopping in Harmer Green
On a fit-out or refurbishment, we follow the services contractors floor by floor. To price a package, call the office on 01277 525 020 or email us with the schedule or marked-up drawings and the specified product data. Tell us what records you need and we’ll confirm with the quote. We work on cable penetrations, pipe penetrations and linear gaps at wall heads, and the failures we are asked to look at most are expanding foam used as fire stopping and fire sealant pulled out of the opening. A specialist sealant contractor works differently from a general builder: in Harmer Green, that means joint design, primers and backing rod as standard.
Smaller places such as Harmer Green still have buildings with fire-resisting walls and floors: schools, halls, care homes and commercial conversions. If sealant is what the specification names, we install it around the services exactly as the maker’s detail sets out.
Every job is signed off with a 12-month guarantee. It’s a plain promise: if our work fails within that year, we put it right.
- Place
- Harmer Green (AL6)
- Wider area
- Hertfordshire
- Guarantee
- 12 months on every job
- Quotes
- Quoted before any work starts
- Call
- 01277 525 020
- Page updated
- 3 November 2026
How the job changes by surface
Cables and cable bundles
Single cables and small bundles are often within a fire-rated sealant’s tested detail. Bundle size, cable type and the space between cables all matter.
Risers and ceiling voids
Service risers and the voids above ceilings are where openings collect. Access to these areas is planned with you in advance.
Towns and villages near Harmer Green
What else we do in Harmer Green
How a job runs
Our CSCS-carded applicators arrive with the sealants, primers and backing rod the job calls for. Joint faces are cleaned back to sound, dry surfaces, primer goes on where the manufacturer specifies it, and the sealant is tooled off neatly. If others near Harmer Green need work, visits can be combined, which keeps travel down. A fixed quote is given before anything starts.
- The specification and schedule come first, so we know which details apply.
- We plan the sequence of floors, risers and voids with you.
- We compare every service penetration with its tested detail before sealing.
- Unsuitable material is removed and the opening cleaned.
- The specified backing and sealant go in to depth and are finished neatly.
- Anything outside the detail is reported to you rather than sealed.
Getting the site ready
- Clear stock, furniture or equipment away from the joints
- Tell us which areas need to stay in use
- For older buildings, check the asbestos register before work
Request a quote
Need a figure for a tender or a budget? Send the scope and any drawings, and we will return a fixed quote you can plan around. If you have questions first, phone 01277 525 020 or email us.
Read more
Harmer Green: questions and answers
Is hospital work, at somewhere like Queen Elizabeth II Hospital, something you do?
Yes. We work in healthcare settings as well as offices and schools. The estates team’s permit system and infection-control rules come first, and the work is planned around them.
Do you cover business parks and estates near Harmer Green, such as Little Ridge Industrial Estate?
Yes. We cover Harmer Green and the area around it, including industrial estates, business parks and retail parks such as Little Ridge Industrial Estate. Send details of the unit and the work through our quote form for a quick quote.
How long do sealant joints last?
It depends on movement, UV and weather, cleaning, traffic and the product. Sealant joints are maintenance items, so inspect them regularly.
Is colour matching possible?
Often, yes. Many products come in a range of standard colours, and matching to RAL references or surrounding finishes is often possible. We’ll confirm the colours available for the specified product.
Is sealant suitable for all service openings?
No. Sealant is the right product only where the tested detail says so. Collars, wraps, batts and boards exist for openings sealant doesn’t cover, and we will tell you when that applies.
Can you reseal penetrations after our M&E works?
Yes, provided a specification covers them. New services after M&E works often breach existing seals and we close them with the specified product.
Does the weather affect the work?
It can, when the joints are outside. Sealant won’t bond properly to a wet or frosty joint, so external work may be moved if conditions aren’t right. Internal work is far less affected.
Honest limits
We check first that sealant really is the fix. It isn’t the answer for:
- Openings that need collars, wraps, batts or boards rather than sealant
- Fire doors, dampers or other fire safety equipment
- Designing or specifying fire stopping, which sits with the designer or fire engineer
Not sure which it is? You can speak to us on 01277 525 020 or send details through our quote form and we will tell you honestly before you book.
What we seal
- Joints between fire-resisting walls and floors
- Small duct penetrations where the tested detail allows
- Cable penetrations
- Linear gaps at wall heads
- Service gaps in risers
- Pipe penetrations
What we are called out for in Harmer Green
Openings in fire-resisting walls normally appear when services are added or changed. New cabling, rerouted pipework or a data route drilled through a riser leaves an opening that nobody returns to. Over a few years of fit-outs, a wall can collect a lot of these.
Most enquiries start with one or more of the following:
- Seals disturbed by maintenance and left open
- Improvised or mixed-product fire seals
- Old intumescent sealant that has split away
- Penetration schedules that need working through
At a university such as University of Hertfordshire, which lies south of Harmer Green, labs, lecture blocks and residences are re-serviced often, so penetration seals are best checked after M&E work.
Before you book anyone
- Will RAMS and insurance details be available?
- Which product they’ll use, and why it suits the joint
- Their plan for phasing and protecting the area
- Whether old or failed sealant will be cut out, not overlaid
Why deal with it now?
An open or wrongly sealed service penetration lets fire and smoke reach the next compartment much sooner than the building was designed for. While the openings can be reached, sealing them is normally straightforward. Left until ceilings are closed or a tenant moves in, the same work costs more access and more disruption. Older rural buildings around Harmer Green move with the seasons, and rigid or tired sealant can’t keep up. The right product, sized to the joint, copes much better.
Every site prices differently: joint size, product, access and site hours all play a part. Send the details and a fixed figure follows.
Why clients in Harmer Green choose us
- 12 months’ guarantee on every job
- One contact handling all your sites
- Health and safety: CHAS accredited
- Products installed to the manufacturer’s instructions
See how commercial sealant jobs are priced and our accreditations.
Compartments and services around Harmer Green
Harmer Green has several hotels close by, all within 2 miles. Hotels are divided into compartments, and refurbishments that add pipes and cables through bedroom and corridor walls leave gaps to close. Harmer Green lies roughly 23 miles out from central London. Office refits around the commuter belt bring new cabling through fire-resisting walls; the gaps need the specified seal.
Wherever services are added at a hospital such as Queen Elizabeth II Hospital (3.4 miles south of Harmer Green) the compartment line has to be made good with the specified product. For a unit at a site such as Little Ridge Industrial Estate, which lies south of Harmer Green, new power or data runs between office and warehouse can breach a compartment wall.
Harmer Green is about 2 miles north of Welwyn Garden City, in Hertfordshire. We cover commercial sites throughout Harmer Green, for single jobs and planned programmes alike. Harmer Green is one of 371 places in Hertfordshire on our list. There’s a separate page for London, about 23 miles away.
We take on service penetrations across the AL6 postcode area. Sites close to Harmer Green are covered too, including Burnham Green (1 mile east), Tewin Wood (1 mile east), Oaklands (1 mile north-west), Bull's Green (1 mile north-east) and Digswell (1 mile south-west). A short drive away, we cover Watford (15 miles south-west), Hemel Hempstead (13 miles south-west), Stevenage (5 miles north), St Albans (8 miles south-west), Bishop's Stortford (15 miles east) and Harpenden (7 miles west).
Around Harmer Green
We work on buildings around Danesbury Park, Monk's Walk School and The White Horse Public House. Harmer Green’s nearest station is Welwyn North station, about 0.8 miles south-west of the centre. Well-known places in the area include Hertford Castle (4.9 miles south-east) and Queen Elizabeth II Hospital (3.4 miles south). Green spaces nearby include Tewin Orchard and Hopkyns Wood.
Site staff or a sealant specialist?
Paperwork matters too. 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.
What you see is the finished bead, but most of the work is hidden. Correct depth, the right primer and a sealant matched to the movement are easy to get wrong without experience.