Greater London · England
Fire Rated Sealant in Harrow on the Hill
Intumescent and fire-rated sealant around gaps, frames and service penetrations for householders, landlords and businesses in Harrow on the Hill. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Gaps flagged on a fire risk assessment
- Cracked or shrunken fire-rated sealant
- New service routes left unsealed after building work
Work for landlords, hotels and businesses
We regularly work with letting and managing agents. Tell us the address, the job and how access works.
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
Fire rated sealant for homes and businesses in Harrow on the Hill
Ordinary silicone or decorators’ caulk in a fire-stopping gap is not a fire-rated seal. We cut out the wrong material and reseal with a fire-rated product tested for that kind of gap. We work on pipe & cable gaps, plasterboard & masonry and linear gaps, and people most often call us about sealant items on a fire risk assessment action list and damaged fire sealant left by other trades.
London blocks of flats carry pipes and cables through walls and floors in their common parts and service risers. In Harrow on the Hill, building managers may need both fire-rated sealant around those openings and new sealant in shared washrooms.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we will put it right.
- Location
- Harrow on the Hill (HA1, HA0, HA2)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quotes
- A clear price before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Harrow on the Hill: your questions answered
Do you work for landlords with property near Sudbury Hill Harrow station?
Yes, landlords and agents are among the people we work for. You can phone 0345 464 0079 or email us with the details for a clear quote.
Can parking be tricky for a visit in Harrow on the Hill?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Can you fill the gap behind a fire door frame?
Yes. Gaps behind architraves are a common job for us. The door and its fittings are a separate job for a door specialist.
Will it make a mess?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
Are you insured?
Yes. Mr Mastic is fully insured.
Where is Mr Mastic based?
We’re a Crawley-based firm. Our area covers South East England, London and Scotland.
Do I have to be there?
It depends on the job. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
Is the work guaranteed?
Yes, for a year. If there’s a problem with our work in that time, tell us and we’ll put it right.
Looking after it afterwards
Aftercare is simple:
- Take photos of fire stopping before ceilings or boxing go back
- Include hidden areas like risers in routine checks
- Report cracked or damaged seals as soon as you notice them
- Keep general-purpose foam and caulk away from fire-stopping gaps
Any fire seal that’s cut or drilled needs resealing to its tested detail. If you need new services through a sealed wall, plan the fire stopping as part of the job.
Any job that breaks through a wall or ceiling should include resealing. Doing it at the time avoids leaving gaps behind.
When something else is needed
To be straight with you, there are a few things sealant will not fix:
- Assessing a building’s fire safety
- Sign-off of the building, which sits with building control or your assessor
- A wall that isn’t a fire-resisting element to begin with
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think before booking.
What we seal
- Linear gaps
- Flats & HMOs
- Plasterboard & masonry
- Door frames
- Service penetrations
- Pipe & cable gaps
Surface by surface
Plasterboard walls
Plasterboard partitions are common in flats, offices and conversions. We use a product tested in that kind of wall for each gap size.
Linear gaps
Long, narrow gaps appear where walls meet slabs and ceilings. We seal them to the tested detail, with backing where it’s needed.
Nearby places to Harrow on the Hill
More services for Harrow on the Hill
Should I try it myself first?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
What happens on the day
At the end, we look at the finished work together. The work normally takes anything from a few hours to several days, depending on how many gaps there are, depending on the amount of work. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Harrow on the Hill. It helps if you can point us to a visitor permit or a bay close to the door.
- We go through the gaps on your list or survey and check each one’s size and substrate.
- Anything that is not fit for the job comes out, and the gap is cleaned.
- Where the tested detail needs backing or fill, we fit it.
- We apply the fire-rated or intumescent sealant to the specified depth and tool it.
- Locations and products are noted so you have them on file.
Preparing for the visit
- Let us know about parking restrictions
- Keep children and pets away from the work area
- Clear the area around the work
Getting a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we’ll explain how we’d tackle it. When it suits you, phone 0345 464 0079 or drop us an email.
Related advice
Commercial buildings in Harrow on the Hill
Many London buildings have tight access and loading restrictions, so out-of-hours working can be arranged where needed. In England, the Regulatory Reform (Fire Safety) Order 2005 requires a fire risk assessment for workplaces and for the common parts of blocks of flats, and gaps around services are often picked up there. We apply fire-rated sealant to the assessor’s or designer’s specification and the product’s tested details.
As a London address, Harrow on the Hill can be tricky for parking: let us know about parking bays, permits or a driveway. For buildings such as Christ Church, gaps around pipes and cables are worth checking after any building work there. Rented homes near Sudbury Hill Harrow station change hands often, and any gap left by new services in shared walls should be closed with a fire-rated product.
Harrow on the Hill is about 1 mile south-east of Harrow, in Greater London. Whether you’re in the middle of Harrow on the Hill or further out, we cover fire rated sealant for every kind of property, from flats and houses to offices and hotels. Our Greater London coverage runs to 764 places, Harrow on the Hill among them. London is on our list too, about 11 miles from Harrow on the Hill.
Jobs for fire rated sealant in HA1, HA0 and HA2 is quoted and booked the same way as anywhere else. Streets in the area include New Road, Amery Road and London Road. Other places close to Harrow on the Hill include Roxeth (1 mile west), Northwick Park (1 mile north-east), South Harrow (1 mile west), Harrow (1 mile north-west) and Sudbury (1 mile south-east). We also work in nearby towns such as London (11 miles south-east), City of Westminster (9 miles south-east), Marylebone (9 miles east), Kensington (7 miles south-east), St Pancras (10 miles east) and Shoreditch (11 miles east).
Local landmarks in Harrow on the Hill
In Harrow on the Hill, that means homes and buildings near Northwick Park, St Dominic's Sixth Form College and Orley Farm School, among other places. For rail, the closest station is Sudbury Hill Harrow station, about 0.5 miles south of the centre. Nearby you’ll also find Kodak Museum (2 miles north) and Clementine Churchill Hospital (under half a mile south-east). The countryside around Harrow on the Hill includes Middle Lake and Northala Fields.
How we quote for fire rated sealant
The price is agreed before any work begins. It takes into account:
- When we can work, for business premises
- How many rooms, windows or areas are involved
- How much there is to do
- Access and height
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we will explain what it covers.
What we need to know
To help us quote quickly, let us know:
- Where the property is
- Access, such as stairs, a lift or height
- Any previous sealing or DIY work
- What the problem is, such as mould, gaps, leaks or cracking
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved before giving you a price.