Greater London · England
Window Mastic in Roundshaw
Mastic around window and door frames, sills and patio doors in Roundshaw, with a 12-month guarantee on every job. Ask us for a quote.
- Mastic that’s falling out in pieces
- Mastic that has split away from the wall
- Rushed sealant from a window installation
What we do, step by step
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours for a few frames, or a day or more for a whole house, and the area is left clean. 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.
- The old mastic is cut out and the surfaces cleaned back.
- Where gaps are deep, backing rod goes in first.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- We clear up and check every joint is fully closed.
Preparing for the visit
- Mention any parking rules near the property
- Plan for the work area to be out of bounds to pets and children
- Clear the area around the work
Ask for a quote
Want a quote for window mastic? Please ring 0345 464 0079 or drop us an email and tell us about the job. We’ll explain what we’d do and give you a clear quote before any work starts.
Related advice
How we handle window mastic in Roundshaw
Frames and walls do not move together. Heat and cold make frames grow and shrink against brick or render that hardly moves. That is why the joint needs a flexible, low-modulus sealant rather than something rigid. We work on composite doors, window sills and patio & French doors, and people most often call us about black, perished sealant on frames and gaps between the frame and the inside reveal.
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, letting in draughts and water.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Location
- Roundshaw (SM6, CR8, CR0)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear price before we start
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Towns and villages near Roundshaw
More services for Roundshaw
Roundshaw homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. Historic houses like Addington Palace (about 3.9 miles east) are a reminder that the area around Roundshaw 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’s traditional sand mastic.
Schools such as Wallington Primary Academy are buildings too, and the mastic around its windows and doors needs looking after like any other building’s. Letting a property close to Wallington station? Then renewing tired window mastic between tenants heads off draught and damp complaints.
Roundshaw is about 2 miles south-west of Croydon, in Greater London. Homes, rented property, offices and hotels in Roundshaw is covered for window mastic, old or new, large or small. The work is guaranteed for a year. Our Greater London coverage runs to 764 places, and Roundshaw is one of them. You can also see our page for London, roughly 10 miles from Roundshaw.
We cover every part of the SM6, CR8 and CR0 postcode area for window mastic. If you need window mastic at a property on Link Lane, Milton Road and Redwing Road or anywhere close by, our applicators can take on the job. Neighbouring places we cover for window mastic include Russell Hill (1 mile east), Bandonhill (1 mile north), Peaks Hill (1 mile south), Waddon (1 mile north-east) and Wallington (1 mile north-west). Further out, we also cover London (10 miles north), City of Westminster (11 miles north), Marylebone (11 miles north), Kensington (11 miles north), St Pancras (12 miles north) and Shoreditch (12 miles north).
Around Roundshaw
Around Roundshaw, our work takes us to homes and buildings near Wilson's School, Waddon Ponds and The John Fisher School. For rail, the closest station is Wallington station, roughly 0.9 miles north-west of the centre. A little further out are Purley War Memorial Hospital (1.2 miles south-east) and Croydon Airport Visitor Centre (0.6 miles east). The countryside around Roundshaw includes Roundshaw Downs and Duppas Hill.
What we’re called out for in Roundshaw
A lot of older mastic was never designed to stay flexible. Once it has hardened, the frame’s movement tears it from the wall, leaving a hairline gap down one side.
Common reasons people contact us include:
- Cold air getting in at the frame edge
- Draughty joints inside around the window
- Cracked or shrunken mastic around the frame
- Untidy mastic left by window fitters
Roundshaw is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Questions to ask before booking
- What the quote includes, VAT included or not
- Is the old sealant removed completely?
- What insurance they hold
- Whether the sealant suits the joint
What the job involves on each surface
Patio & French doors
Water at the foot of a door frame isn’t always the mastic: blocked drain slots, worn brush seals and threshold details can let water in too. We check before we reseal.
Aluminium frames
Large aluminium doors have long joints down each side and across the head, and the bottom joint sees the most water. Each is cleaned, backed where deep and resealed.
Landlords, agents and businesses in Roundshaw
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
We work for landlords and letting agents as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
Your questions about window mastic in Roundshaw
Can parking be tricky for a visit in Roundshaw?
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.
Can you do window mastic in Roundshaw?
Yes. Our work covers London and the South East, and Roundshaw is part of that. You can call 0345 464 0079 or email us and let us know what needs doing.
Are you insured?
Yes. We’re fully insured, and we can confirm the details when we quote.
Do you seal inside as well as outside?
Yes. Indoors, we seal between the frame and the plaster or reveal, using a paintable sealant if you want to decorate.
How many windows can you do in a day?
It depends on access, the old mastic and the size of the frames. We will tell you how long your job needs when we quote.
Can resealing stop a draught around my window?
It will if the frame joint is the problem. We find where the air is coming from before we reseal.
Can I add another job to the visit?
Yes, we can. Several rooms, windows or areas can go on one quote.
Do you take out the old sealant first?
Yes. We cut out all the old sealant and clean the joint before applying anything new.
Can I do it myself?
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.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
What sealant work can’t fix
Before you book, it’s worth knowing the limits too:
- A sash or casement that won’t close properly
- Penetrating damp from a failed cavity tray or render
- A frame that has rotted at the joint
If you are not sure, just call 0345 464 0079 or email us and we will give you a straight answer.
Where we work in Roundshaw
- Window sills
- uPVC windows
- Timber windows & doors
- Composite doors
- Aluminium frames
- Patio & French doors
Why act early in Roundshaw
The work is quick compared with the damage it prevents: it takes anything from an hour or two to a full day, depending on how many frames there are. Leave it until water is coming in and you may need plastering and decorating as well. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in Roundshaw, the repair is bigger than the sealant job would have been.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed. Call for a quick quote and we will go through it with you.
Why book with us
- We agree the colour with you first
- Rated 4.9 stars on Google
- Domestic, commercial and hotel work
- One-year guarantee on every job
See what affects the cost and what customers say.