Oxfordshire · England
Sand mastic for sash & case windows in Lewknor, Oxfordshire
Specialist sand mastic for Lewknor: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Draughty sash windows at the surround
- Cracked mastic round a front door frame
- Gaps between timber frames and stone or brick
About our sand mastic in Lewknor
Burnt sand mastic is a traditional material that sits naturally against stone and brick. It’s a good fit for period properties where a modern sealant bead would stand out. If you’re dealing with draughty sash windows at the surround and mastic dropping out of the joint, we can help, whatever the surface.
In a village or hamlet like Lewknor, older cottages and farmhouses often have timber windows set in stone or brick. Older buildings like these do not always suit modern silicone, so the sealant has to be chosen to suit the building.
We stand behind the work with a 12-month guarantee, so you’re not left on your own once the job is done.
- Location
- Lewknor (OX49)
- Wider area
- Oxfordshire
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
Towns and villages near Lewknor
Other services in Lewknor
Frames and glazing around Lewknor
The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. 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.
For site and facilities teams at buildings such as Lewknor Church of England Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Lewknor is about 5 miles south of Thame, in Oxfordshire. Homes, rented property, offices and hotels in Lewknor is covered for sand mastic, old or new, large or small. Every job comes with our one-year guarantee. Lewknor is one of 443 towns and villages in Oxfordshire we cover. For nearby work, see our Oxford page (12 miles or so).
Postcode districts we cover here for sand mastic: OX49. Streets in the area include High Street, Weston Road and Lewknor Close, all of which we cover. Other places close to Lewknor include 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). Further out, 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).
Landmarks near Lewknor
In Lewknor, that means homes and buildings near Ye Olde Leathern Bottle Public House and Icknield Community College and the streets around them. Nearby you will also find Thame Community Hospital (5 miles north). The countryside around Lewknor includes Aston Rowant NNR and Bald Hill.
How to look after the new joints
A little care helps the new joints last. We recommend:
- Look over the window mastic once a year
- Ask the planning authority about consent for listed or conservation-area homes
- Clear gutters so water doesn’t pour onto the windows
- Leave the new mastic unpainted
Keep gutters and sills clear so water runs away from the surround. Water sitting against the mastic shortens its life.
Good mastic helps keep the frame dry. Failed mastic lets water reach the timber and timber that stays wet can rot.
What we’re called out for in Lewknor
Sand mastic slowly weathers. It hardens, cracks and starts to come away from the frame or the masonry.
People normally contact us when they notice one of these:
- Mastic dropping out of the joint
- Gaps between timber frames and stone or brick
- Silicone on a period window that looks wrong
- Draughty sash windows at the surround
If you live in an older home near Church of St Margaret, the joint between an old wall and a newer frame is usually the first place rain gets in.
Comparing quotes
- What the cure time is
- Who does the work, and how experienced they are
- How the surfaces are prepared before sealing
- How the colour is chosen
For landlords and businesses
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We’ve worked in hotels as well as homes and businesses.
Housing providers, facilities teams and property managers book us too. Several sites can be quoted together, and we are fully insured for the work.
What we do, step by step
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. Typically it takes a few hours per window, depending on the condition of the joints, and the area is left clean. For a village or hamlet like Lewknor, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We start by checking each surround and agreeing the joints to renew.
- We rake out the old mastic and clean the joint.
- We pack any deep gaps so the mastic sits at the right depth.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
Before we arrive
- Mention any tricky access
- Clear items away from the joints we are working on
- Let us know about parking restrictions
Ask for a quote
Want a quote for sand mastic? Please call 0345 464 0079 or email us with a few details. We’ll explain what we’d do and give you a clear price before work begins.
Related advice
Honest limits
We’ll always be straight with you, so here’s what new sealant won’t do:
- Damaged stone surrounds
- Whether work needs listed building consent
- Cracked or broken glass
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer.
Where we work in Lewknor
- Brick reveals
- Stone surrounds
- Tenement windows
- Sash and case windows
- Timber door frames
- Period & listed homes
FAQs for Lewknor
Will you come out to Lewknor?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
What guarantee comes with sand 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.
When will the new mastic be hard?
It forms a skin fairly soon and it hardens fully over a longer time. Timing depends on the weather and the joint.
Do I need to be at home?
Access is agreed with you when the job is booked. For inside work, that normally means someone being in.
Do you take out the old sealant first?
Yes, every time. New sealant won’t bond properly to old, so any old material comes out before anything new goes in.
Is there any odour?
That depends on the sealant. Some products have a noticeable smell, others very little, and any smell fades as they cure.
What’s sand mastic made of?
Sand plus a binder based on linseed oil. It’s built up in the joint by hand and shaped to suit the surround.
What does sand mastic cost?
Size, access and the old material all affect the cost. Call for a quick quote.
Leave it or put it right?
Not every draught comes from the sashes themselves. Open mastic joints round the box can let air in, and renewing the mastic closes them. Where a wall is exposed, as many are in small places like Lewknor, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all play a part, and we’ll explain the quote if you ask.
What you get with us
- Fully insured
- 20+ years of sealant experience
- Domestic, commercial and hotel work
- Anti-fungal silicone where joints get wet
Read our cost guide and what customers say.