Greater London · England
Window Mastic in Dulwich
We cover Dulwich for mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly.
- Damp patches on the reveal after heavy rain
- Old mastic that has gone black or come away
- Draughty joints inside around the window
FAQs for Dulwich
Is parking a problem for a job in Dulwich?
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.
Do you work for landlords with property near West Dulwich station?
Yes, we work for landlords and agents. You can ring 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before work begins.
Will resealing my frames help with draughts?
It will if the frame joint is the problem. We find where the air is coming from before we reseal.
Do you have sealant for grey or black windows?
Yes, in most cases. Tell us the frame colour when you get in touch and we will use the nearest match.
Will it make a mess?
We keep the work tidy. We protect what’s around the joints.
What information do you need?
The location, the problem and the rough size of the job. Photos by email help too.
Does someone need to be in?
We need access to the joints, so we will agree that with you when we book. Indoors, that normally means someone at home.
Can you do upstairs windows?
Yes, where it’s safe. For high or awkward windows, we will tell you what access is needed.
How we handle window mastic in Dulwich
Homes in Dulwich have every kind of window: uPVC, aluminium, timber and composite, along with patio doors, French doors and sills. Each gets a sealant chosen for the frame and the wall it meets. Typical jobs include a bead that doesn’t match the frame and draughts coming in around windows and doors, on composite doors, uPVC windows and timber windows & doors.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first.
We stand behind the work with a one-year guarantee.
- Place
- Dulwich (SE22, SE21, SE23)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Quotes
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What else we do in Dulwich
How it works
Once we’re on site, we compare the joints with what we discussed. If we find something unexpected, we talk it through with you first. After that, the work takes most of a day for a typical house, less for a few frames. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- We check each frame and agree which ones need doing.
- We remove the old mastic and clean the frame and the wall.
- Where gaps are deep, backing rod goes in first.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- Every joint is checked before we leave.
Before we arrive
- Where the joints are inside, avoid wetting them before we arrive
- Mention any sign-in or site rules at work premises
- Plan for the work area to be out of bounds to pets and children
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Related advice
What affects the cost of window mastic
You’ll get a clear quote before we start. It takes into account:
- The product the joint needs
- The number of rooms or windows
- Mould in or behind the old joints
- Any working-time requirements on site
Rather than a set price list, we look at what your job involves: the amount of work, the old material and the access. You will know the price before we begin.
Helping us quote
Photos by email are helpful but not essential. Try to tell us:
- Access, such as stairs, a lift or height
- Roughly how big the job is
- Any previous sealing or DIY work
- What the problem is, such as mould, gaps, leaks or cracking
Need a quote? Please ring 0345 464 0079 or send us an email and tell us about the job. We’ll explain what we’d do and send you a clear quote before work begins.
Dulwich homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before you book. 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.
If you let a flat or house near West Dulwich station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. For an older house near a landmark such as Christ's Chapel of God's Gift, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Dulwich is about 1 mile south-east of Herne Hill, in Greater London. Dulwich gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Across Greater London, we cover 764 places, Dulwich among them.
We work across the SE22, SE21 and SE23 postcode area for window mastic. That includes homes and businesses on Court Lane, Druce Road and Boxall Road and the roads around them. You’ll find Dulwich on the A2216, so it’s easy for us to get to. Other places close to Dulwich include 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). Larger places within reach include 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).
Landmarks near Dulwich
Typical jobs here are in homes near The Crown and Greyhound pub, Dulwich Park and Alleyn's School, among other places. The closest station to Dulwich is West Dulwich station, about 0.7 miles south-west. A little further out are Dulwich Community Hospital (0.9 miles north) and Greenwich Castle (4 miles north-east). Not far away are Knight's Hill and Centre for Wildlife Gardening.
Landlord and commercial work in Dulwich
Hotels need rooms back in use, so we plan the work room by room. Hotel work is part of what we do, alongside homes and businesses.
Letting agents often deal with us directly. Tell us the address, the job and how access works.
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Common problems we fix in Dulwich
Timber windows bring their own problems. Mastic painted over many times cracks with the paint, and timber moves with moisture as well as temperature.
It’s worth asking for a quote if you see:
- Draughty joints inside around the window
- Gaps where the sill meets the wall
- Rushed sealant from a window installation
- Sealant in the wrong colour for the frame
As a London address, Dulwich can be tricky for parking: let us know about parking bays, permits or a driveway.
Questions to ask before you book
- Is the old sealant removed completely?
- When the joint can take water or movement
- Whether they’re fully insured
- What preparation is included
How the job changes by surface
Composite doors
Composite doors are normally hung in an uPVC-type frame, and the joint around it is sealed like a window. The bead is colour-matched to the frame.
Aluminium frames
Aluminium needs a sealant that bonds to coated metal, and acetoxy silicones aren’t used, as they can attack some metals. We use a neutral-cure product.
Aftercare tips
Simple care keeps the joints in good condition. We recommend:
- Keep solvents and bleach off the sealant
- Keep drainage slots and sill grooves clear
- Air rooms to keep condensation down around windows
- Wash the frames with mild soapy water
Keep sill grooves and drainage slots clear, so rain drains out rather than building up at the sealant.
Look out for the warning signs: cracks in the mastic, gaps you can see light through, damp on the reveal or mould around the inside of the frame. If you notice one, it’s time to get the joint looked at.