Greater London · England
Window Mastic in Swiss Cottage
Mastic around window and door frames, sills and patio doors for Swiss Cottage, backed by a 12-month guarantee. Ask us for a quote.
- Mastic that’s falling out in pieces
- A bead that doesn’t match the frame
- Gaps left after new windows were fitted
About our window mastic in Swiss Cottage
The mastic around a window or door seals the gap between the frame and the wall. Once that seal fails, wind and rain find the gap. Our applicators cut it out and replace it with a flexible, weatherproof sealant. If you’re dealing with hard, cracked sealant around windows and cracked internal joints between frame and plaster, we can help.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Location
- Swiss Cottage (NW3, NW8, NW6)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quote
- A clear price before work begins
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Window mastic in Swiss Cottage: local notes
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. In a converted house or block, who looks after the windows depends on the lease, so check that before you book.
If you look after a building such as The UCL Academy, the mastic around its windows and doors needs looking after like any other building’s. For an older house near a landmark such as Church of All Souls, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Swiss Cottage is about 1 mile south of Hampstead, in Greater London. For window mastic in and around Swiss Cottage, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We cover Greater London from our Crawley base, Swiss Cottage included. Our area takes in 764 places across Greater London, from the larger towns to small villages.
Every address in NW3, NW8 and NW6 is covered for window mastic, from the main roads to the quietest streets. We cover properties on Avenue Road, Acacia Road and Harben Road. Nearby, we also carry out window mastic in South Hampstead (1 mile north), St John's Wood (1 mile south), Haverstock (1 mile east), Belsize Park (1 mile east) and Primrose Hill (1 mile east). We also work in nearby towns such as London (4 miles south-east), Kensington (3 miles south-west), St Pancras (3 miles south-east), Shoreditch (4 miles east), Walthamstow (7 miles north-east) and Hoxton (4 miles east).
Local landmarks in Swiss Cottage
Typical jobs here are in homes near Cafe Med pub, Holy Trinity CofE Primary School and Primrose Hill and the streets around them. Other local landmarks include Cecil Sharp House (1.1 miles east) and St. Mary's Town and Country School (under half a mile north-east). Swiss Cottage has its own railway station: South Hampstead station. Other landmarks nearby include Montfichet's Tower (3.7 miles south-east) and Isokon Gallery (0.8 miles north-east). The countryside around Swiss Cottage includes The Long Water and Primrose Hill.
Honest limits
We won’t take on work that will not last, so here’s what sealant can’t put right:
- Penetrating damp from a failed cavity tray or render
- Rotten timber, which needs a joiner first
- Worn gaskets, brush seals or a door that has dropped
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer before booking.
Where we work in Swiss Cottage
- Aluminium frames
- Patio & French doors
- Timber windows & doors
- uPVC windows
- Composite doors
- Window sills
Landlords, agents and businesses in Swiss Cottage
For anyone letting property in or around Swiss Cottage, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs.
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
How the visit works
When we arrive, we start by going over the job with you, so you know exactly what we are doing. Surfaces next to the work are protected before we start. Most jobs take a few hours for a few frames, or a day or more for a whole house. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Swiss Cottage. A visitor permit or a nearby bay makes the visit run more smoothly.
- First we look at every frame and agree the list.
- Next the failed sealant is cut away and the joint cleaned.
- Deep gaps are filled with backing rod to set the depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Every joint is checked before we leave.
Preparing for the visit
- Mention any sign-in or site rules at work premises
- Mention any tricky access
- Tell us about any previous sealing or DIY attempts
Get a quote
If you are in Swiss Cottage and need window mastic, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you will get a clear quote before we start.
Advice
Questions from Swiss Cottage
Is Swiss Cottage in your area for window mastic?
Yes. We work across London and the South East, and Swiss Cottage is part of that. You can phone 0345 464 0079 or drop us an email and tell us what needs doing.
Can parking be tricky for a visit in Swiss Cottage?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
What does window mastic cost?
It depends on the job, so we quote each one individually. To get one, phone 0345 464 0079 or email us and tell us what needs doing and where.
Should I try DIY first?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Do you have sealant for grey or black windows?
Yes. We can use white, brown, anthracite grey, black or clear.
Do you have insurance?
Yes. We’re fully insured for domestic and commercial work.
Can you do several jobs on one visit?
Yes. Tell us about everything you’d like done and you’ll get one quote.
I’m a tenant. Can you help?
Of course. Ask your landlord first, and we can send them the quote if that helps.
How the job changes by surface
uPVC windows
Some uPVC windows were sealed at fitting with a quick bead that never bonded. It comes out, deep gaps get backing rod and the joint is resealed.
Window sills
Masonry sills can have joints where water gets in, and the joint under the frame can let rain run behind. Those are sealed with a product suited to stone or concrete.
Towns and villages near Swiss Cottage
Also in Swiss Cottage
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
How we quote for window mastic
There’s no set price list. The quote depends on:
- How much there is to do
- How many areas need sealing
- Whether there’s mould to deal with
- The old material and how stubborn it is
Commercial jobs are quoted on the same basis as homes: 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 go through it with you.
What to tell us for a quote
There’s no need for technical detail. Just tell us:
- Where the job is, and your postcode
- What the problem is, such as mould, gaps, leaks or cracking
- Whether it has been sealed before
- Any access issues, like height or stairs
Need a quote? Please phone 0345 464 0079 or send us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
When to call us in Swiss Cottage
Older frames were often sealed with products that set hard. Once it’s rigid, every bit of frame movement pulls at it, leaving a hairline gap down one side.
Most people get in touch when they notice something like this:
- Gaps left after new windows were fitted
- Water coming in at the bottom corners of a door
- Cracked internal joints between frame and plaster
- Hard, cracked sealant around windows
If you let a flat or house near South Hampstead station, renewing tired window mastic between tenants heads off draught and damp complaints.
Questions to ask before you book
- Who does the work, and how experienced they are
- Whether all the old sealant comes out first
- How long to leave it before use
- Whether you can choose the colour