Greater London · England
Window Mastic in Morden
Window mastic for Morden, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Cold air getting in at the frame edge
- White mastic on grey or black frames
- Leaking joints at the ends of sills
Window mastic in Morden
The new joint does not have to be white. We can seal in white, brown, anthracite grey, black or clear, so the line suits the frame instead of standing out. Common call-outs are for mastic that’s falling out in pieces and cracked sealant at the sill ends, on patio & French doors, composite doors and aluminium frames.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. The mastic around them dries out and cracks with age, which is when draughts and damp patches appear in homes in Morden.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Place
- Morden (SM4, SM3, SW20)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What window mastic looks like in Morden
Compared with the north and west, the South East gets less rain, 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 booking.
As a London address, Morden can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Rented homes near St Helier station change hands often, and renewing tired window mastic between tenants heads off draught and damp complaints.
Morden is about 2 miles south of Wimbledon, in Greater London. Anywhere in SM4, we cover window mastic for homes and businesses. Our Greater London coverage runs to 764 places, and Morden is one of them. We also work in London, around 9 miles away.
All of SM4, SM3 and SW20 is within our area for window mastic. If you need window mastic at a property on London Road, Epsom Road and Holne Chase or a nearby road, we can help. Morden sits on or near the B279, so getting to you is simple. We also cover Lower Morden (1 mile south-west), Sutton Common (1 mile south-east), North Cheam (2 miles south), Worcester Park (2 miles south-west) and Stoneleigh (3 miles south-west). We also work in nearby towns such as London (9 miles north-east), City of Westminster (9 miles north), Marylebone (9 miles north), Kensington (7 miles north), St Pancras (10 miles north-east) and Shoreditch (11 miles north-east).
Landmarks near Morden
In Morden, that means homes and buildings near Lord Nelson pub, Glenthorne High School and Cannon Hill Common. There’s a railway station in Morden itself: St Helier station. A little further out are St. Anthony's Hospital (1 mile south-west) and Chessington Castle Hill (4.3 miles south-west). Open spaces near Morden include Henman Hill and Morden Park (park).
Nearby places to Morden
What else we do in Morden
When something else is needed
We’d rather tell you now than do work that won’t last, so here’s what sealant can’t put right:
- Penetrating damp from a failed cavity tray or render
- A sash or casement that will not close properly
- Condensation trapped between the panes
If in doubt, phone 0345 464 0079 or drop us an email and we will say what we think before you book.
Where we work in Morden
- uPVC windows
- Window sills
- Timber windows & doors
- Aluminium frames
- Composite doors
- Patio & French doors
What happens on the day
When we arrive, we start by going over the job with you. Surfaces next to the work are protected before any work begins. Most jobs take most of a day for a typical house, less for a few frames. In Morden, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- First we look at every frame and agree the list.
- Next the failed sealant is cut away and the joint cleaned.
- Where gaps are deep, backing rod goes in first.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- Finally we tidy up and check each joint.
Preparing for the visit
- Tell us if parking is tricky
- Tell us about any previous sealing or DIY attempts
- Mention any leaks or damp you’ve noticed
Getting a quote
Asking for a quote is easy: let us know the job and the location. Photos by email help us understand the job, and we’ll take it from there.
Advice
FAQs for Morden
Do you work for landlords with property near St Helier station?
Yes, we work for landlords and letting agents. Just ring 0345 464 0079 or drop us an email and tell us about the property, and we’ll give you a clear price.
Is Morden in your area for window mastic?
Yes. We work across London and the South East, and Morden is part of that. Just call 0345 464 0079 or email us with a few details of the job.
How long should I leave it?
Cure times vary by product and the temperature. Before we leave, we’ll tell you the cure time.
How long will my window job take?
A few frames take a few hours. You will get a timescale with the quote.
Can I add another job to the visit?
Yes. More than one area can be quoted together.
Where is Mr Mastic based?
We work from Crawley. Our applicators cover Morden, along with the rest of our area.
Is the new sealant paintable?
It depends on the sealant. Some hybrid sealants can be painted; silicone can’t. Tell us if you are decorating and we will choose accordingly.
Can you reach windows above the ground floor?
Normally, yes. We plan safe access before the job, so mention the height and anything in the way.
What the job involves on each surface
uPVC windows
Fitters’ mastic on plastic frames is sometimes thin and rushed. It comes out, deep gaps get backing rod and the joint is resealed.
Timber windows & doors
Older timber windows in stone or brick can suit sand mastic rather than modern sealant. We’ll tell you which suits your home.
For landlords and businesses
Mouldy or split sealant often shows up at the end of a tenancy. Several properties can be quoted together.
We work for letting agents and landlords as well as homeowners. Sealant work between tenants keeps a property looking cared for.
Signs you need window mastic in Morden
A lot of older mastic was never designed to stay flexible. Once it’s rigid, every bit of frame movement pulls at it, and a gap opens along one edge.
The most common problems we see are:
- Gaps left after new windows were fitted
- Hard, cracked sealant around windows
- Mastic that’s falling out in pieces
- Whistling draughts around closed windows
For an older house near a landmark such as St Lawrence Church, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Questions to ask before booking
- How hidden problems are handled
- Who does the work, and how experienced they are
- How the surfaces are prepared before sealing
- What product goes in the joint
Leave it or put it right?
Failed mastic is not a reason to replace sound windows. If the frames and glass are in good order, resealing the joints is often all that is needed. If we find failed glass units or worn seals, we’ll tell you. In a flat in Morden, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
A few things move the cost up or down: the old material and how easily it comes out, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Why Morden clients choose us
- 180+ five-star Google reviews
- White, clear, grey or coloured to suit, where the product allows
- 20+ years of sealant experience
- We agree the colour with you first
Looking after it afterwards
After the cure time, these simple habits help:
- Wash the frames with mild soapy water
- Repaint timber before it’s bare
- Clear any debris from frame drain holes
- Do not paint over the silicone
Clean the frames with mild soapy water, and keep solvents and harsh chemicals off the joint.
On timber windows, water behind the joint can lead to rot. Rotten timber needs a joiner, not a sealant, so it pays to reseal before that happens.