Greater London · England
Window & door mastic in Coulsdon, Greater London
Professional window mastic in and around Coulsdon, with every bit of old sealant taken out first and a one-year guarantee.
- Draughts coming in around windows and doors
- Old mastic that has gone black or come away
- Mastic that has split away from the wall
How we handle window mastic in Coulsdon
Some gaps around frames are far deeper than they look. Filling it with sealant alone leaves a joint that can’t move properly, so we fit backing rod to set the right depth. That way the new bead bonds to the frame and the wall only. We work on composite doors, uPVC windows and aluminium frames, and people most often call us about whistling draughts around closed windows and rain getting in at the frame or under the sill.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Coulsdon.
Every job is covered by a 12-month guarantee, wherever you are in Greater London.
- Location
- Coulsdon (CR5, CR8, CR3)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Window mastic in Coulsdon: local notes
Historic houses like Nonsuch Mansion (about 4.9 miles north-west) are a reminder that the area around Coulsdon has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For site and facilities teams at buildings such as Smitham Primary School, larger buildings have plenty of frames, and the mastic around each one ages. Rented homes near Coulsdon South station change hands often, and renewing tired window mastic between tenants heads off draught and damp complaints. Coulsdon is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Coulsdon is about 13 miles south of London, in Greater London. Coulsdon gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Our area takes in 764 places across Greater London. For nearby work, see our London page.
Work in CR5, CR8 and CR3 works the same way as everywhere else we cover. Window mastic is available to properties on Hadleigh Grove, Farthing Way and Dobson Close. With the B276 and B2030 close by, Coulsdon is simple for us to get to. Other places close to Coulsdon include Woodcote (1 mile north), Old Coulsdon (1 mile south-east), Woodmansterne (1 mile west), Chipstead (1 mile south-west) and Purley (2 miles north-east). We also work in nearby towns such as London (13 miles north), City of Westminster (14 miles north), Marylebone (14 miles north), Kensington (13 miles north), St Pancras (15 miles north) and Shoreditch (15 miles north).
Local landmarks in Coulsdon
Typical jobs here are in homes near Dollypers Hill, Coulsdon Sixth Form College and The Pembroke pub and the streets around them. Coulsdon has its own railway station: Coulsdon South station. Well-known places in the area include Croydon Airport Visitor Centre (3 miles north) and Purley War Memorial Hospital (2 miles north-east). For a walk, there’s Duppas Hill and Mercers Lake.
Should I try it myself first?
If you’re set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it doesn’t work out, we can still put it right.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Common questions in Coulsdon
Do you cover Coulsdon for window mastic?
Yes, Coulsdon is within the area we cover. Our work covers London and the South East. Just call 0345 464 0079 or email us with a few details of the job, and we’ll send you a clear quote.
Can parking be tricky for a visit in Coulsdon?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot.
Can you seal over the old sealant?
No. New silicone won’t bond to old silicone, and anything trapped underneath, including mould and water, stays there. We remove it all first.
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.
Can you do several jobs on one visit?
Yes, and it often makes sense. Doing several areas at once is usually more efficient, so mention them when you ask for a quote.
Do you work for hotels and businesses?
Yes. We can plan bigger jobs in stages to suit the site.
Do you have sealant for grey or black windows?
Yes. White, brown, anthracite grey, black and clear sealants are all available, so the joint suits the frame.
Are you fully insured?
Yes. We are fully insured.
Also near Coulsdon
Other services in Coulsdon
Landlord and commercial work in Coulsdon
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together, and we are fully insured for the work.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we’ll give you a quote.
What we cannot put right
Sealant isn’t the answer to every problem, and we will tell you before work begins. Sealant will not put right:
- Damp problems in the wall away from the window
- Broken hinges, locks or handles
- Worn gaskets, brush seals or a door that has dropped
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
Where we work in Coulsdon
- Patio & French doors
- Window sills
- Aluminium frames
- Timber windows & doors
- uPVC windows
- Composite doors
What happens on the day
The work is kept neat and contained to the area we’re working on. The job usually takes a morning for a couple of windows and a door. In Coulsdon, 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.
- We remove the old mastic and clean the frame and the wall.
- Where gaps are deep, backing rod goes in first.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Finally we tidy up and check each joint.
Preparing for the visit
- Move anything stored near the joints
- Mention any leaks or damp you’ve noticed
- Mention any parking rules near the property
Get a quote
We quote each job on its own, so the first step is telling us about yours. Just phone 0345 464 0079 or drop us an email with the details.
Related advice
Why act early in Coulsdon
Redecorating is a good moment to renew the mastic. Fresh joints finish the job neatly, and it’s easier while the walls are being worked on anyway. In London conversions, one flat’s bathroom is often above another flat’s ceiling, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble for homes in Coulsdon.
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you are not sure whether it needs doing, call 0345 464 0079 or send us an email for an honest opinion and a quote.
Why us?
- Over 20 years’ experience
- Sanitary silicone with an anti-fungal additive in wet areas
- One-year guarantee on every job
- We agree the colour with you first
What affects the cost of window mastic
You’ll get a clear quote before work begins. It takes into account:
- Mould in or behind the old joints
- The size of the job
- Access and height
- How many rooms, windows or areas are involved
Doing several joints on one visit generally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. We’ll give you a clear quote for the lot.
Asking for a quote
What to tell us when you ask for a quote:
- The problem you’ve noticed
- Where the property is
- Any access issues, like height or stairs
- A few photos by email, if you can
There’s no standard price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or email us.
What the job involves on each surface
Timber windows & doors
Wood swells when it’s wet and shrinks when it dries, so the joint must stay flexible. The paint or stain needs to be sound where the sealant meets it.
Patio & French doors
The joints around patio doors run a long way, top, sides and threshold. The threshold and the bottom corners take the most water, so we pay close attention there.