Slough · England
Colnbrook External Mastic
External mastic in Colnbrook from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Gaps where render, brick and frames meet
- Water getting into walls through failed joints
- Joints where the bead has come unstuck
The process
A visit follows a simple pattern: we check the joints, protect the area around them, carry out the job and clear up. Most jobs take anything from a few hours to several days, depending on the building. For a village or hamlet like Colnbrook, the journey is planned in advance: 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.
- First we look over the joints with you, agree which to renew and talk through access.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Before we arrive
- Let us know if you’ve seen damp or leaks
- Plan for the work area to be out of bounds to pets and children
- Mention any tricky access
Get a quote
We don’t publish a price list, because every job is different. Instead, we send you a clear quote for your job. To get started, call 0345 464 0079 or drop us an email.
Advice
External mastic in Colnbrook, done properly
A movement joint is a deliberate break that lets a wall expand and contract. Its sealant has to flex with the building, season after season, and when it fails, the wall takes the strain and water finds a way in. Common call-outs are for joints where the bead has come unstuck and panel joints letting water in, across brickwork movement joints, render & cladding joints and façade panels.
Somewhere as small as Colnbrook, homes and farm buildings often face open ground, where walls and rooflines take the weather head on. Gutter joints and wall joints there need a sealant that can flex and stay put.
The work is covered for a year after we finish. If anything is not right with it, ring 0345 464 0079 or drop us an email.
- Where
- Colnbrook (SL3)
- Wider area
- Slough
- Guarantee
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
How we quote for external mastic
You’ll get a clear quote before we start. It’s based on:
- How easy the joints are to reach
- The amount of work
- How many rooms, windows or areas are involved
- The product the joint needs
Every job is a little different, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference.
What we need to know
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- Whether it’s a home or a business
- What’s wrong with the joints now
- The address or postcode of the job
- How we’d reach the joints
For external mastic in Colnbrook, ring 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
Colnbrook questions
Do you work for landlords with property near Sunnymeads station?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
Do you cover Colnbrook for external mastic?
Yes, Colnbrook is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or send us an email with a few details of the job.
Can I add another job to the visit?
Yes. Several rooms, windows or areas can go on one quote.
Can you seal joints between two different materials?
Yes. Materials like render, brick, metal and uPVC all move differently, so the joint between them must be flexible. We choose one that suits both surfaces.
Do you hold any approvals?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
What’s an expansion joint in brickwork?
Most straight vertical gaps in brickwork are movement joints. It lets the bricks expand without cracking, and it should be sealed with a flexible sealant.
Are you insured?
Yes. We’re fully insured.
Do I need to be at home?
That depends on where the joints are. For work indoors, someone needs to let us in, and for outside work we’ll agree access with you when we book.
Landlord and commercial work in Colnbrook
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance.
Landlords and letting agents in Colnbrook can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for.
External mastic in Colnbrook: local notes
Historic houses like Frogmore House (about 3 miles west) are a reminder that the area around Colnbrook has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. 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.
Rented homes near Sunnymeads station change hands often, and split movement joints are easy to miss on a rental until damp shows inside. Schools such as Colnbrook Church of England Primary School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing. Homes close to Church of St Thomas include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Colnbrook is about 4 miles north of Staines-upon-Thames, in Slough. Wherever you are in the SL3 postcode area, our applicators can take on external mastic. Colnbrook is one of 31 towns and villages in Slough where we work for external mastic. We also work in London, about 19 miles from Colnbrook.
Postcode districts we cover here for external mastic: SL3. Streets in the area include High Street, Rayners Close and Drift Way, all of which we cover. Other places close to Colnbrook include Poyle (1 mile south-east), Brands Hill (1 mile west), Horton (1 mile south-west), Stanwell Moor (2 miles south-east) and Ditton (2 miles west). Larger places within reach include Slough (4 miles north-west), Cippenham (5 miles north-west), Chalvey (4 miles north-west), Britwell (5 miles north-west), Upton (3 miles north-west) and Burnham (7 miles north-west).
Local landmarks in Colnbrook
Typical jobs here are in homes near Arthur Jacob Nature Reserve, The Red Lion Public House and Langley Grammar School, among other places. Colnbrook’s nearest station is Sunnymeads station, roughly 1.7 miles south-west of the centre. Nearby you’ll also find Windsor Castle (3.4 miles west) and Upton Hospital (3.2 miles north-west). For a walk, there’s Uxbridge Moor and Staines Reservoirs.
Towns and villages near Colnbrook
Other services in Colnbrook
Leave it or put it right?
It often makes sense to reseal all the failing joints on an elevation together. They’ve weathered the same way and it means sorting access once. Older cottages and farmhouses around Colnbrook can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote and we’ll talk you through it.
Why Colnbrook clients choose us
- An ARBOMaster approved applicator
- We never seal over old sealant
- 180+ five-star Google reviews
- Fully insured
Take a look at our cost guide and our reviews.
Keeping the joints in good condition
Good habits help new joints last longer. A few tips:
- Look over the joints every year, ideally after winter
- Keep movement joints as flexible joints, not mortar
- Wash walls gently around the sealant
- Ask before painting over external sealant
Keep pressure washers away from the sealant. High-pressure water can lift the edges and let water in behind.
Gaps, plants or missing sealant in a joint are worth getting looked at. Earlier resealing means a smaller job and a better result.
Can I do it myself?
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
A DIY attempt does not rule out a professional job. We cut it out and start again, so just mention it when you contact us.
What we cannot put right
A few problems are outside what sealant work can do:
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cracking across the wall rather than at a joint
- Loose or hollow render, which needs re-rendering
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we will tell you honestly.
Joints and surfaces we work on
- Concrete & block
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
- Façade panels