Oxfordshire · England
Westcot Window Mastic
We cover Westcot for mastic around window and door frames, sills and patio doors. Old material cut out, joints cleaned and sealed neatly and a 12-month guarantee.
- Leaking joints at the ends of sills
- Hard, cracked sealant around windows
- Draughts coming in around windows and doors
How we handle window mastic in Westcot
Over two decades of sealing frames has taught us which products suit which walls. We are ARBOMaster approved and fully insured, and we give a one-year guarantee on the work. If you have hard, cracked sealant around windows and leaking joints at the ends of sills, we can put it right, on window sills, aluminium frames and composite doors alike.
Mastic can only go onto a dry, clean joint, so window work in Westcot is booked around the forecast. Let us know about access to all the frames, upstairs ones included.
Our work is backed for twelve months.
- Where
- Westcot (OX12)
- Region
- Oxfordshire
- Guarantee
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Westcot homes and the weather
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 the older streets around Church of the Holy Rood, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Westcot is about 4 miles west of Wantage, in Oxfordshire. Homes, rented property, offices and hotels in Westcot can book us for window mastic. The work is guaranteed for a year. Across Oxfordshire, we cover 443 places, and Westcot is one of them. You can also see our page for Oxford, about 16 miles away.
Postcode districts we cover here for window mastic: OX12. We also cover Sparsholt (1 mile east), Kingston Lisle (1 mile west), Woolstone (3 miles west), Upper Lambourn (5 miles south) and Sheepdrove (5 miles south). Within a short drive, we also cover Didcot (11 miles east), Abingdon-on-Thames (12 miles north-east), Witney (14 miles north), Carterton (13 miles north), Wantage (4 miles east) and Grove (4 miles east).
Local landmarks in Westcot
Well-known places in the area include Faringdon Day Hospital (5.8 miles north-west) and Uffington Museum (2.5 miles west). For a walk, there’s Rams Hill and Letcombe Valley.
Questions from Westcot
Is there a guarantee on window mastic in Westcot?
Every job comes with our one-year guarantee, wherever it is. We’re also fully insured and ARBOMaster approved.
Is Westcot within the area you cover?
Yes, Westcot is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Are you insured?
Yes. Full insurance covers our work.
Can you match the sealant to my frames?
Yes, we choose a colour to suit the frame. Anthracite grey, black, brown and white cover most frames, with clear as an option.
Will resealing my frames help with draughts?
Yes, if the air is getting in around the frame. If it’s through the window’s own seals or a hinge, that’s a different fix, and we’ll say so.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover Westcot and the rest of Oxfordshire.
Can I add another job to the visit?
Of course. Combining jobs makes good use of the visit, so mention them when you ask for a quote.
Will there be a smell?
Sometimes, a little. It fades as the sealant cures, and ventilation helps.
Common problems we fix in Westcot
Joint shape matters as much as the product. A thin smear across a wide gap has nothing to it, while a joint packed solid can’t stretch. Backing rod sets the right depth.
It’s worth asking for a quote if you see:
- A bead that does not match the frame
- Rain getting in at the frame or under the sill
- Gaps between the frame and the inside reveal
- Draughts coming in around windows and doors
If you look after a building such as The Ridgeway Church of England (C) Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Before booking anyone
- How much experience the applicator has
- Are they insured?
- Is the old sealant removed completely?
- The length of the guarantee
Aftercare tips
Good habits help new joints last longer. A few tips:
- Don’t aim a pressure washer at the joints
- Keep paint off silicone joints
- Air rooms to keep condensation down around windows
- Check the mastic once a year
Clean the frames with mild soapy water, and avoid solvent cleaners on the sealant.
Signs to watch for: 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.
What else we do in Westcot
DIY versus a professional finish
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
Different surfaces, different methods
Composite doors
Front doors take the weather head on. Those corners get the most care.
Aluminium frames
Aluminium moves with heat, and the frames are often slimmer than uPVC. A tidy bead in anthracite grey, black or a matching colour suits the frame.
How we quote for window mastic
We do not publish a price list. What we look at:
- Whether there’s mould to deal with
- The old material and how stubborn it is
- Working hours on commercial sites
- How easy the joints are to reach
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs. Ask us for a quote and we will explain what it covers.
What we need to know
What to tell us when you ask for a quote:
- Where the property is
- Pictures of the joints, sent by email
- What’s wrong with the joints now
- Whether it has been sealed before
The more we know about the job, the more useful the quote. Let us know the location, the problem and roughly how many joints, and email pictures if that is easy.
What happens on the day
All our tools and materials come with us in the van, so you don’t need to buy or prepare anything. After a quick look at the joints together, we protect the area and start. It normally takes a few hours for a few frames, or a day or more for a whole house. In a small place like Westcot, access is generally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First we look at every frame and agree the list.
- We remove the old mastic and clean the frame and the wall.
- We fit backing rod in deep gaps so the sealant is the right depth.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- Every joint is checked before we leave.
How to prepare
- Let us know if you’ve seen damp or leaks
- For business premises, tell us about site rules or sign-in
- For indoor joints, keep the area dry beforehand if you can
Get a quote
To get a quote, ring 0345 464 0079 or drop us an email with the location and a short description of the problem. We’ll give you a clear quote before any work starts.
Advice
Why it’s worth doing now in Westcot
Running fresh sealant over the old joint is tempting, but new sealant can’t bond to old, crumbling mastic. It soon lifts and the leak carries on behind it. Proper resealing starts with removing the old joint. In a small place like Westcot, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all make a difference.
Why choose Mr Mastic in Westcot
- We leave the area clean and tidy
- A 12-month guarantee on all work
- ARBOMaster approved applicator
- Domestic, commercial and hotel work