Fire Stopping in Dulwich
Fire stopping in Dulwich, backed by over 20 years in commercial sealing. Fully insured, with a 12-month guarantee.
- Open linear gaps along the top of fire-resisting walls
- Expanding foam used as fire stopping
- Snag lists that include open service penetrations
Fire stopping across Dulwich
Tell us what needs sealing and where, with photos or drawings if you have them, and we’ll price it.
Fire stopping in Dulwich
Where pipes, cables and other services cross a compartment wall or floor, the opening around them has to be closed so fire and smoke can’t move between compartments. Our part is installing fire-rated and intumescent sealant at those openings and along linear gaps, where the specification calls for it. Each seal follows the manufacturer’s tested detail. The enquiries we see most involve seals that don’t match their tested detail and fire-rated sealant that has cracked or shrunk back, across small duct penetrations where the tested detail allows, joints between fire-resisting walls and floors and cable penetrations. Sealant contractors, mastic applicators, sealant specialists: whatever the job title on the order, the work in Dulwich is the same: failed joints cut out, faces prepared and the right sealant laid to the right depth.
After a fit-out or new cabling in a London building, risers and ceiling voids are where open service gaps tend to be found. If sealant is the specified product we fit it to its tested detail, and if the detail needs something else, you will hear it from us.
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.
- Where
- Dulwich (SE22, SE21, SE23)
- Wider area
- Greater London
- Cover
- 12 months on our workmanship
- Quotes
- Fixed quote, scope in writing
- Call
- 01277 525 020
- Updated
- 3 November 2026
After the work
Regular inspection catches problems early. In particular:
- Don’t let anyone top up a fire seal with the wrong product
- Report damaged or disturbed seals as soon as they’re spotted
- Check risers and ceiling voids after each round of works
- Arrange inspection before areas are covered up
New services after handover are a common way fire stopping gets breached. Building it into each contractor’s sign-off keeps the walls intact.
Looking at service areas on a regular cycle pays off. A cracked or disturbed seal found early is a small job compared with dozens found at once.
How the quote is worked out
A fixed quote reflects the actual work. It allows for:
- Removal of failed or old sealant
- Any access equipment needed
- Phasing around occupants
- The size and state of each joint
We don’t publish prices, because the scope varies so much from one building to the next. For a fixed figure, call for a quote.
Sending details for a quote
Diagnosis starts before we arrive. Tell us:
- What the building is and how it’s used
- Any dates the work must fit around
- Specification clauses that apply
- The postcode of the building
Need a figure for a tender or a budget? Send the scope and any drawings, and we’ll return a fixed quote you can plan around. If you have questions first, ring 01277 525 020 or email the details over.
Service penetrations in Dulwich buildings
Approved Document B is the English guidance that covers fire stopping around openings and penetrations. Its BS 476 references are being withdrawn from 2 September 2029, with BS EN 13501-2 classification taking over, subject to transitional arrangements. What we install is set by the specification, and it goes in to the tested detail. London’s office and residential buildings are refitted constantly, and each round of cabling or pipework can leave open penetrations. We seal to the specification and the product’s tested detail, working within the building’s permits.
Colleges such as William Booth College, 1.6 miles to the north of Dulwich, add IT and services as courses change, and each new penetration through a fire-resisting wall needs sealing with the specified product. Hospital estates such as Maudsley Hospital, 1.7 miles to the north of Dulwich, are divided into fire compartments, and any service penetration through them should be sealed to the specified, tested detail. Where a unit on an estate such as Goose Green Trading Estate (1 mile north of Dulwich), has fire-resisting walls between offices and warehouse, any new service through them should be sealed to the tested detail.
Dulwich is about 1 mile south-east of Herne Hill, in Greater London. Our applicators travel to Dulwich for work on service penetrations. We work across 764 places in Greater London.
We cover the SE22, SE21 and SE23 postcode districts for service penetrations. Streets here include Court Lane, Druce Road and Boxall Road. Access to Dulwich is via the A2216, so getting applicators and materials to site is simple. We also cover Dulwich Village (1 mile north-west), West Dulwich (1 mile south), Herne Hill (1 mile north-west), Sydenham Hill (1 mile south-east) and Forest Hill (1 mile east). Further afield, our area takes in London (4 miles north), City of Westminster (6 miles north-west), Marylebone (6 miles north-west), Kensington (7 miles north-west), St Pancras (6 miles north) and Shoreditch (6 miles north).
Near you in Dulwich
We work on buildings around The Crown and Greyhound pub, Dulwich Park and Alleyn's School, among other places. For rail, the closest station is West Dulwich station, roughly 0.7 miles south-west of the centre. Well-known places in the area include Dulwich Community Hospital (0.9 miles north) and Greenwich Castle (4 miles north-east). The countryside around Dulwich includes Knight's Hill and Centre for Wildlife Gardening.
Our process
Site rules come first: signing in, inductions and any permit to work. With the paperwork done, the joints are worked through in the order agreed with your site contact, and each area is checked before we leave it. For a job in Dulwich, access comes first. Give us the hours we can be on site and we will schedule to suit.
- We read the specification, drawings or penetration schedule you send and ask about anything unclear.
- Every penetration is compared with its detail: wall or floor type, service, gap size and depth.
- 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.
- We apply the specified sealant to the depth and around the services as the detail shows.
- Openings that need a collar, wrap, batt or other product are flagged to you rather than filled with sealant.
Preparing the site
- Send asbestos survey details if the building is pre-2000
- Tell us which areas need to stay in use
- Point out parking and an unloading spot
Quotes
Tell us about the building, the joints and when you need the work done, and we’ll put a fixed quote together. The easiest way is to call 01277 525 020 or email a schedule or drawings.
Related advice
Places near Dulwich
What else we do in Dulwich
Owners, agents and contractors
As a CHAS accredited contractor and Constructionline member, we’re straightforward to vet for your supplier list. 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.
Dulwich: questions and answers
Will you take on work at estates like Goose Green Trading Estate, close to Dulwich?
Yes. We cover Dulwich and the area around it, including industrial estates, business parks and retail parks such as Goose Green Trading Estate. To start, just give us a call on 01277 525 020 or email us with the unit, the joints involved and your access times.
How does the move away from BS 476 affect penetration seals in Dulwich?
References to BS 476 classes are being removed from Approved Document B from 2 September 2029, after which BS EN 13501-2 classification is the route, subject to transitional arrangements. Whichever applies, we install the specified product to its tested detail; the specification is for the designer to set.
Can you work to our specification?
Yes. Include it with the drawings when you ask for a quote, and we will price the work to it.
Do you seal on top of existing sealant?
No. Overlaying old sealant is a frequent cause of early failure, so it all comes out first.
Is Dulwich in your area?
Yes. Dulwich falls within our area, and you can phone 01277 525 020 or email a schedule or drawings to get started.
Can the building stay open while you work?
Yes, with some planning. We agree a sequence with your contact so just one area at a time is disrupted.
How long do sealant joints last?
It depends on movement, UV and weather, cleaning, traffic and the product. Treat them as maintenance items and inspect them regularly.
Different surfaces, different methods
Small ducts
Small ductwork can sometimes be sealed with sealant where the tested detail includes it. Larger or fire-rated ductwork typically needs a different solution set by the designer.
Drylining partitions
Holes in board are often cut larger than needed. If the gap exceeds the tested range, sealant alone won’t do, and the detail may call for board patching or another product.
Why deal with it now?
Open penetrations multiply: every new cable or pipe adds another. Keeping on top of it after each round of works keeps the job small. Failed sealant in a building in Dulwich can quickly affect neighbours, tenants or the floor below. Putting it right early is less disruptive than dealing with the consequences.
Pricing service penetrations depends on how many there are, their condition and the access. Call for a quote.
Why choose Mastic Doctor in Dulwich
- Joints cleaned back to sound surfaces
- CHAS accredited contractor
- One contact handling all your sites
- Products installed to the manufacturer’s instructions
Read how commercial sealant jobs are priced or our accreditations.