Oxfordshire · England
Window & door mastic in Cassington, Oxfordshire
Window mastic for Cassington, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Leaking joints at the ends of sills
- Sealant in the wrong colour for the frame
- Untidy mastic left by window fitters
Window mastic for homes and businesses in Cassington
Around Cassington we seal all kinds of frames: uPVC, aluminium, timber and composite, along with patio doors, French doors and sills. Each gets a sealant chosen for the frame and the wall it meets. We work on timber windows & doors, composite doors and patio & French doors, and people most often call us about mastic that’s falling out in pieces and white mastic on grey or black frames.
Somewhere as small as Cassington, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
We guarantee the work for a year. If something is not right with it in that time, tell us and we will put it right.
- Where
- Cassington (OX29)
- Wider area
- Oxfordshire
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Landlords, agents and businesses in Cassington
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.
Different surfaces, different methods
Window sills
Masonry sills can have joints where water gets in, and the joint under the frame can let rain run behind. We seal those with a sealant suited to masonry.
Patio & French doors
Door frames take knocks and movement every time the doors are used. The sealant must cope with it, where a rigid one would crack.
Keeping the joints in good condition
To keep the joints looking good and working properly:
- Keep paint off silicone joints
- Keep paint and stain on wooden frames in good order
- Check the mastic once a year
- Ventilate rooms so frames don’t stay wet inside
Check the drainage slots in the frames aren’t blocked, so water can run away instead of sitting against the joint.
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.
Why act early in Cassington
Draughts and leaks do not always mean new windows. If the frames and glass are in good order, resealing the joints is often all that is needed. Problems with the glass or gaskets are for a window company, and we’ll say so. Where a wall is exposed, as many are in small places like Cassington, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and send you a clear quote before any work starts.
Why Cassington customers choose us
- Fully insured
- Neat joints and a tidy finish
- A choice of colours where the product allows
- Old sealant always removed completely
What happens on the day
Before we leave, we go over the finished joints with you and explain the cure time. The work normally takes a few hours for a handful of frames, longer for a whole house, depending on the size of the job. Somewhere like Cassington needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- We check how each frame can be reached safely.
- All the failed sealant is cut away, along with any loose debris.
- Frame and wall are cleaned and must be dry before sealing.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
How to prepare
- Clear the area around the work
- Let us know about stairs, lifts or work at height
- Tell us if parking is tricky
Getting a quote
For a quote, call 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before any work starts.
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Places near Cassington
Also in Cassington
Questions from Cassington
Can you help a landlord with a rental near Hanborough station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or drop us an email and tell us about the property, and we will give you a clear quote.
Is Cassington in your area for window mastic?
Yes, Cassington is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we’ll give you a clear quote.
How long before the joint can be used?
It depends on the product and the conditions. Before we leave, we’ll tell you the cure time.
Do you have sealant for grey or black windows?
Yes. Anthracite grey, black, brown and white cover most frames, with clear as an option.
Can I do it myself?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Do you guarantee window mastic?
Yes. Every job comes with our 12-month guarantee, and we are ARBOMaster approved applicators.
Can I add another job to the visit?
Yes. Tell us about everything you’d like done and we’ll quote it together.
Can I paint over the new sealant?
It depends on the sealant. Silicone isn’t paintable, but some hybrid sealants are. Tell us if you’re decorating and we will choose accordingly.
Can I do it myself?
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Windows and doors in Cassington
London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Historic houses like Blenheim Palace (about 3.4 miles north) are a reminder that the area around Cassington 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.
If you look after a building such as St Peter's Church of England Primary School, its window and door frames need their mastic kept sound, just like a home’s. For landlords with property near Hanborough station, renewing tired window mastic between tenants heads off draught and damp complaints.
Cassington is about 6 miles north-west of Oxford, in Oxfordshire. We carry out window mastic for homes and businesses in Cassington and nearby, as part of our work across Oxfordshire. Cassington is one of 443 places in Oxfordshire we cover for window mastic. Oxford is on our list too, around 6 miles away.
Our applicators cover all of the OX29 postcode area for window mastic. Local streets include Church Lane, The Green and Pound Lane. Close by, we work in Swinford (1 mile south-west), Eynsham (2 miles south-west), Wytham (2 miles south-east), Farmoor (2 miles south) and Filchampstead (3 miles south). Further out, we also cover Oxford (6 miles south-east), Didcot (13 miles south), Bicester (11 miles north-east), Abingdon-on-Thames (8 miles south), Witney (6 miles west) and Carterton (11 miles west).
What’s near Cassington
We work in homes and buildings around Bartholomew School and Chequers Inn. For rail, the closest station is Hanborough station, about 2.5 miles north-west of the centre. Well-known places in the area include Oxford Castle and earlier settlement remains (4.5 miles south-east) and Radcliffe Infirmary (4.1 miles south-east). Not far away are Hook Meadow and The Trap Grounds and Cumnor Hill.
Signs you need window mastic in Cassington
Timber windows bring their own problems. Mastic painted over many times cracks with the paint, and timber moves with moisture as well as temperature.
Keep an eye out for any of the following:
- Black, perished sealant on frames
- Hard, cracked sealant around windows
- Rushed sealant from a window installation
- Whistling draughts around closed windows
For an older house near a landmark such as Church of St Peter, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
What your quote should include
- What preparation is included
- Whether you can choose the colour
- How long the guarantee is
- How much experience the applicator has