Oxfordshire · England
Window & door mastic in Lewknor, Oxfordshire
Mastic around window and door frames, sills and patio doors for homes and businesses in Lewknor and across Oxfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Cracked internal joints between frame and plaster
- Sealant in the wrong colour for the frame
- Cold air getting in at the frame edge
How we handle window mastic in Lewknor
Most frames have an outside joint and an inside one. The external joint is the weather seal; the internal joint closes the gap to the plaster and stops draughts. We seal one or both, depending on what’s needed. If you are dealing with water coming in at the bottom corners of a door and draughts coming in around windows and doors, we can put it right.
Outdoor sealant needs dry, clean surfaces, so work on frames around Lewknor is planned for dry weather. Tell us about access to every side of the house, including upper-floor windows.
You get a 12-month guarantee, the same in Lewknor as everywhere else we work.
- Location
- Lewknor (OX49)
- Region
- Oxfordshire
- Guarantee
- A year, on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How to look after the new joints
Aftercare is simple, and it makes a real difference:
- Check the mastic once a year
- Keep paint off silicone joints
- Avoid blasting the frames with a pressure washer
- Clear any debris from frame drain holes
On timber frames, keep the paintwork in good order, since wood that gets wet swells and shrinks more. Paint up to the joint, not over the silicone.
Wet, windy weather is when failed mastic shows itself, but sealant goes on best when frames and walls are dry. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
What the job involves on each surface
Window sills
Sills catch the water running down the glass, so the joints at each end and underneath matter. Each is cleaned out and resealed.
Patio & French doors
Patio and French doors have the longest joints on most houses. Most leaks start at the bottom corners, so they get particular care.
Landlords, agents and businesses in Lewknor
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. Several properties can be quoted together.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
Also near Lewknor
Other services in Lewknor
What happens on the day
When we get to you, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. Most jobs then take a morning for a couple of windows and a door. In a small place like Lewknor, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We check each frame and agree which ones need doing.
- 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.
- Every joint is checked before we leave.
How to prepare
- Let us know about stairs, lifts or work at height
- Keep children and pets away from the work area
- Tell us about any water getting in
Getting a quote
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 send us an email.
Related advice
Quotes for window mastic in Lewknor
Call for a quick quote. What matters most is:
- The size of the job
- The old material and how stubborn it is
- Whether the work is at height
- Any working-time requirements on site
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. The price is agreed before we begin.
What we need to know
There’s no need for technical detail. It helps if you can tell us:
- Any previous sealing or DIY work
- How we’d reach the joints
- Pictures of the joints, sent by email
- Where the job is, and your postcode
Call for a quick quote, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved.
Should I try it myself first?
If you’ve already had a go yourself, that is fine. We cut it out and start again, so just mention it when you contact us.
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.
Common questions in Lewknor
What guarantee comes with window mastic in Lewknor?
All our work, in Lewknor and everywhere else, comes with a 12-month guarantee. We are also fully insured and ARBOMaster approved.
Is Lewknor in your area for window mastic?
Yes. Our work covers London and the South East, and Lewknor is part of that. You can ring 0345 464 0079 or email us and let us know what needs doing, and we’ll give you a clear price.
Where do you work from?
We’re a Crawley-based firm, with over 20 years’ experience. We work across South East England, London and Scotland.
I’m a tenant. Can you help?
We can work for tenants, landlords or agents. Get your landlord’s agreement first.
Can you work on commercial sites?
Yes, regularly. Larger jobs can be planned room by room or area by area to suit the site.
Do the sealants smell?
There can be a smell while the sealant cures, which fades as it sets. Ventilation helps.
Can you match the sealant to my frames?
Yes, in most cases. Tell us the frame colour when you get in touch and we will match it as closely as we can.
Are you fully insured?
Yes. Full insurance covers our work.
Window mastic in Lewknor: local notes
With historic houses such as Adwell House (about 1.6 miles north-west) nearby, there’s older building stock in the area around Lewknor as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Schools such as Lewknor Church of England Primary School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s. For an older house near a landmark such as Church of St Margaret, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Lewknor is about 5 miles south of Thame, in Oxfordshire. Across the OX49 area, our applicators can take on window mastic. 443 places in Oxfordshire are on our list. You can also see our page for Oxford, roughly 12 miles from Lewknor.
Our applicators cover all of the OX49 postcode area for window mastic and the streets around it. Whether your property is on High Street, Weston Road and Lewknor Close or a nearby road, we can help. If you’re just outside Lewknor, we cover South Weston (1 mile north-west), Aston Rowant (1 mile north-east), Postcombe (1 mile north), Shirburn (1 mile south-west) and Kingston Blount (2 miles north-east). Within a short drive, we also cover Oxford (12 miles north-west), Didcot (13 miles west), Abingdon-on-Thames (13 miles west), Thame (5 miles north), Henley-on-Thames (10 miles south) and Benson (7 miles south-west).
What’s near Lewknor
Typical jobs here are in homes near Ye Olde Leathern Bottle Public House and Icknield Community College. Nearby you will also find Thame Community Hospital (5 miles north). The countryside around Lewknor includes Aston Rowant NNR and Bald Hill.
Why act early in Lewknor
Choosing the product is half the job. Decorators’ caulk and bathroom silicone aren’t designed for outside joints that move. An exterior, low-modulus sealant stays flexible in sun and frost. Around Lewknor, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
Doing several joints on one visit usually makes better use of the time than several visits, so tell us about everything that needs sealing. We’ll send you a clear quote for the lot.
Why choose Mr Mastic in Lewknor
- 20+ years of sealant experience
- Colour agreed with you before we start
- Trusted Arbo and Everbuild sealants
- We never seal over old sealant