Windsor and Maidenhead · England
External Mastic in Sunninghill
External mastic in Sunninghill from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Movement joints with cracked, split or missing sealant
- Failed seals between different materials
- Sealant that has lost its bond to the brick or render
External mastic for homes and businesses in Sunninghill
Movement joints let brickwork, render and cladding expand and shrink without cracking. Its sealant has to flex with the building, season after season, so once it splits or hardens, the joint stops working and water gets in. We work on façade panels, copings & trims and concrete & block, and the jobs we see most are joints where the bead has come unstuck and failed seals between different materials.
Outbuildings, garages and conservatories around homes in places like Sunninghill add more joints to look after. Gutter ends, garage door frames and the joints where an extension meets the house are typical spots for leaks.
Big or small, it’s backed by our 12-month guarantee in Sunninghill and across Windsor and Maidenhead.
- Location
- Sunninghill (SL5)
- Region
- Windsor and Maidenhead
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Common problems we fix in Sunninghill
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it cannot stretch and tears as soon as the joint widens.
If you can see any of these, it’s time to have the joints looked at:
- Damp patches traced to an open external joint
- Gaps where render, brick and frames meet
- Sealant pulling away from one side of the joint
- Movement joints filled with mortar instead of sealant
Homes close to Church of St Michael and All Angels include some older properties, and the joints between older walls, newer extensions and the roofline need a sealant that can move.
What your quote should include
- Is VAT in the price?
- How the colour is chosen
- Whether they’re fully insured
- Who turns up on the day
What the job involves on each surface
Joints between dissimilar materials
Different materials may need different primers. Both surfaces are cleaned and primed as the product requires.
Concrete and blockwork
Concrete and block walls shrink as they dry and move with temperature. We reseal their joints with backing rod and a flexible product.
Places near Sunninghill
More services for Sunninghill
Elsewhere in Windsor and Maidenhead
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About external & façade joints
Work for landlords, hotels and businesses
Letting agents and landlords in Sunninghill can book us as well as householders. Sealant work between tenants is a simple way to keep a property in good order before the next move-in.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
What happens on the day
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours to a few days, depending on the length of joint and the access, and the area is left clean. In a smaller place like Sunninghill, parking is seldom the issue; lanes, gates and long drives are worth mentioning. For outside work, side access and the height of the joints help us plan.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Getting ready for the visit
- Mention if the joints have been sealed before
- Let us know about stairs, lifts or work at height
- Tell us if parking is tricky
How to get a quote
Asking for a quote is easy: tell us what needs doing and where. Photos by email help us understand the job, and we’ll take it from there.
Related advice
What we can’t put right
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Rising or penetrating damp from elsewhere in the wall
- Structural movement, which needs a surveyor or engineer
- Cracked brickwork or render that needs a builder or plasterer
If you are not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
What we seal
- Render & cladding joints
- Joints between brick and frames
- Concrete & block
- Brickwork movement joints
- Façade panels
- Copings & trims
Sunninghill: your questions answered
Do you cover smaller places like Sunninghill?
Yes, Sunninghill is covered. Our work covers London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Is Sunninghill in your area for external mastic?
Yes, Sunninghill is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or email us and tell us what needs doing, and we will send you a clear quote.
What information do you need?
Where the job is, what the problem is and roughly how big it is. If you can, email a few pictures.
Are you ARBOMaster approved?
Yes. We are an ARBOMaster approved applicator.
Where is Mr Mastic based?
We are a Crawley-based firm, with over 20 years’ experience. We work across South East England, London and Scotland.
Is there a guarantee?
Yes, always. There’s a 12-month guarantee on every job, wherever you are.
Do I need to be at home?
If the work is inside, we need someone to let us in. After that, you can carry on with your day.
Do you work at height?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher ones, send details and we will confirm the access.
Should I try it myself first?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Sunninghill buildings and the weather
With historic houses such as St Leonard's Hill (about 4.6 miles north) nearby, there’s older building stock in the area around Sunninghill as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. 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.
For site and facilities teams at buildings such as St Michael's CofE Primary School, larger buildings have long runs of movement joint that eventually need resealing. Letting a property close to Ascot station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Sunninghill is about 4 miles east of Bracknell, in Windsor and Maidenhead. Every kind of property in Sunninghill is covered for external mastic. Every job comes with our one-year guarantee. We cover 57 towns and villages across Windsor and Maidenhead, from the larger towns to small villages. There’s also a page for Reading, roughly 14 miles from Sunninghill.
We cover every part of SL5 for external mastic. Streets in the area include High Street, London Road and School Road, all of which we cover. We also cover the places around Sunninghill: Ascot (1 mile north-west), Beggar's Bush (1 mile east), Cheapside (1 mile north), Blacknest (1 mile east) and North Ascot (2 miles north-west). Within a short drive, we also cover Maidenhead (9 miles north), Windsor (5 miles north), Boyn Hill (8 miles north-west), Cookham (11 miles north), Furze Platt (10 miles north) and Dedworth (5 miles north).
Local landmarks in Sunninghill
Typical jobs here are in homes near St Mary's School, Charters School and Silwood Park. The nearest railway station is Ascot station, about 1 mile west of the centre. Other landmarks nearby include Heatherwood Hospital (1.5 miles north-west). Open spaces near Sunninghill include Virginia Water Lake and Gracious Pond.
Why deal with it now?
A failed movement joint lets water into the wall. Dealing with it early keeps the repair to the joint, rather than the wall around it. In an older home around Sunninghill, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
A failed joint rarely gets cheaper to fix by waiting. If you are unsure, ring 0345 464 0079 or email us for an honest opinion and a quote.
Why choose Mr Mastic in Sunninghill
- Over 20 years’ experience
- White, clear, grey or another colour, product permitting
- An ARBOMaster approved applicator
- Anti-fungal silicone where joints get wet
Take a look at how sealant jobs are priced or customer reviews.