Oxfordshire · England
Window & door mastic in Merton, Oxfordshire
Window mastic for Merton and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Gaps between the frame and the inside reveal
- Cold air getting in at the frame edge
- Old mastic that has gone black or come away
What the job involves on each surface
Window sills
Stone and concrete sills have their own joints, and the joint under the frame can let rain run behind. We seal those with a sealant suited to masonry.
Composite doors
An exposed front door gets wind-driven rain. Those corners get the most care.
Window mastic in Merton
The mastic around a window or door seals the gap between the frame and the wall. When it cracks, hardens or pulls away, draughts and rain get in. The old mastic is removed and the joint resealed with a flexible exterior sealant. We’re often asked to deal with sealant in the wrong colour for the frame and damp patches on the reveal after heavy rain, on patio & French doors, uPVC windows and window sills.
In a village or hamlet like Merton, older cottages and farmhouses often have timber windows set in stone or brick. Older buildings like these don’t always suit modern silicone, so the sealant has to be chosen to suit the building.
Your job is guaranteed for a year, as with all our work.
- Where
- Merton (OX25)
- Region
- Oxfordshire
- Cover
- A year, on every job
- Price
- A clear price before work begins
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Quotes for window mastic in Merton
Call for a quick quote. The main things that affect it are:
- The amount of work
- The number of rooms or windows
- The type of sealant required
- How easy the joints are to reach
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What we need to know
To help us quote quickly, please include:
- Any previous sealing or DIY work
- Access, such as stairs, a lift or height
- A few photos by email, if you can
- The address or postcode of the job
Need a quote? Please ring 0345 464 0079 or drop us an email with a few details. We’ll explain what we’d do and send you a clear quote before work begins.
Keeping the joints in good condition
Good habits help new joints last longer. A few tips:
- Keep timber frames painted
- Don’t aim a pressure washer at the joints
- Use gentle cleaners on frames and sealant
- Do not use solvent cleaners on the joint
Timber frames need their paint kept up, since wood that gets wet swells and shrinks more. Paint up to the joint, not over the silicone.
A small gap around a frame only grows. As old mastic keeps shrinking, the gap widens, and a cold room gets colder. A new joint closes it up.
Windows and doors in Merton
Historic houses like Boarstall Tower (about 3.7 miles south-east) are a reminder that the area around Merton 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. 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.
Homes close to Church of St Swithin include some older properties, and the joint between an old wall and a newer frame is usually the first place rain gets in.
Merton is about 3 miles south of Bicester, in Oxfordshire. Whether you are in the middle of Merton or further out, we cover window mastic for every kind of property, from flats and houses to offices and hotels. 443 places in Oxfordshire are on our list. We also work in Oxford, about 8 miles from Merton.
Every address in OX25 is covered for window mastic, from the main roads to the quietest streets. Neighbouring places we cover for window mastic include Fencott (1 mile south), Murcott (1 mile south-east), Charlton-on-Otmoor (1 mile south-west), Wendlebury (2 miles north-west) and Lower Arncott (2 miles east). Larger places within reach include Oxford (8 miles south), Bicester (3 miles north), Abingdon-on-Thames (13 miles south), Witney (15 miles west), Thame (11 miles south-east) and Kidlington (6 miles south-west).
Near you in Merton
Around Merton, our work takes us to homes and buildings near The Old Plough pub. The closest station to Merton is Bicester Village station, roughly 2.7 miles north of the centre. Other landmarks nearby include Bicester Community Hospital (2.9 miles north) and Bicester Avenue (2.3 miles north). Green spaces nearby include Graven Hill and Woodsides Meadow.
Common problems we fix in Merton
Every frame moves through the day. A plastic or aluminium frame lengthens in sunshine and shortens as it cools, while the masonry beside it stays put. If the sealant cannot stretch, it splits.
Most people get in touch when they notice something like this:
- Mastic that is falling out in pieces
- Water coming in at the bottom corners of a door
- Rushed sealant from a window installation
- Gaps between the frame and the inside reveal
Letting a property close to Bicester Village station? Then cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
What to look for in a quote
- Is the old sealant removed completely?
- How long to leave it before use
- How the surfaces are prepared before sealing
- The length of the guarantee
Can I do it myself?
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
Why it’s worth doing now in Merton
Failed mastic is not a reason to replace sound windows. Where the frames are sound, new mastic normally deals with draughts and leaks at the edges. If we find failed glass units or worn seals, we’ll tell you. Around Merton, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
A failed joint rarely gets cheaper to fix by waiting. 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?
- You choose the colour before work begins
- Approved under the ARBOMaster scheme
- 180+ five-star Google reviews
- Fully insured
See how sealant jobs are priced and our reviews.
Questions from Merton
Do you cover Merton for window mastic?
Yes, Merton is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or send us an email and tell us what needs doing.
Will you come out to Merton?
Yes. Merton is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do the sealants smell?
Sometimes, a little. Any smell clears as the sealant cures.
Is it messy?
Tidy work is part of the job. Nearby surfaces are protected, and the area is left clean when we finish.
Can you work on commercial sites?
Yes. Hotels, offices and other businesses use us.
Where do you work from?
We’re a Crawley-based firm, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Do I have to be there?
That depends on where the joints are. For work indoors, someone needs to let us in.
Can resealing stop a draught around my window?
In many cases. The gap between frame and wall is a common source of draughts, and sealing the inside and outside joints closes that path.
The process
We bring everything the job needs with us, so you don’t need to buy or prepare anything. After a quick look at the joints together, we protect the area and start. Most jobs take anything from an hour or two to a full day, depending on how many frames there are. Somewhere as small as Merton, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We start by checking each window and door with you.
- 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.
- Finally we tidy up and check each joint.
Getting ready for the visit
- Keep pets and children clear of the area while we work
- Clear the area around the work
- Let us know if you’ve seen damp or leaks
Get a quote
There’s no standard price list, because every job is different. Instead, we give you a clear price for your job. To get started, ring 0345 464 0079 or email us.