Greater London · England
External Mastic in Roxbourne
External mastic across Roxbourne and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Movement joints filled with mortar instead of sealant
- Gaps where render, brick and frames meet
- Water getting into walls through failed joints
Can I do it myself?
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
How we handle external mastic in Roxbourne
Joints in render and cladding are easy to overlook until a damp patch appears. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant in a matching colour. Typical jobs include brick movement joints where the sealant has split and rigid filler in a joint that should flex, across copings & trims, façade panels and render & cladding joints.
Outside work in London starts with access: side passages, upper floors and where to park. In Roxbourne, joints up high may need ladders or other access, which is worth talking through when you book.
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
- Roxbourne (HA5, HA2, HA4)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Work for landlords, hotels and businesses
We work for landlords and agents as well as homeowners. Sealant work between tenants is a simple way to keep a property in good order.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
What we can’t put right
Some problems need a builder, plumber or other trade rather than us:
- Rising or penetrating damp from elsewhere in the wall
- Loose or hollow render, which needs re-rendering
- Cracked brickwork or render that needs a builder or plasterer
If you’re not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer before you book.
What we seal
- Copings & trims
- Façade panels
- Joints between brick and frames
- Concrete & block
- Brickwork movement joints
- Render & cladding joints
Different surfaces, different methods
Copings and trims
Copings expand and contract through the day, so a flexible sealant suits them best in all weathers.
Joints between dissimilar materials
Wherever two materials meet, they move differently. We seal the joint with a flexible exterior sealant.
How the visit works
The work is kept neat and contained to the joints we’re treating, so you can carry on as normal. The job generally takes a few hours for a handful of joints, longer for a whole elevation. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Roxbourne. It helps if you can point us to a visitor permit or a bay close to the door.
- First we look over the joints with you, agree which to renew and talk through access.
- Old sealant and any debris are cut and raked out.
- We clean both faces of the joint and prime them where the product calls for it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Preparing for the visit
- Keep children and pets away from the work area
- Let us know if you’ve seen damp or leaks
- Where the joints are inside, avoid wetting them before we arrive
Get a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we will talk you through what we’d do. When it suits you, call 0345 464 0079 or email us.
Advice
When to call us in Roxbourne
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and rips as the joint opens.
Common reasons people contact us are:
- Failed sealant between panels on a façade
- Old sealant gone brittle and cracked
- Cracked joints where brick meets render or frames
- Water getting into walls through failed joints
For an older house near a landmark such as St. Andrew’s Church, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Before you book anyone
- Whether they’re fully insured
- What the quote includes, VAT included or not
- Whether they seal over old material or remove it
- What preparation is included
Places near Roxbourne
Also in Roxbourne
Leave it or put it right?
Mortar or ordinary filler might look like a quick way to close an open joint, but it stops the joint moving. The movement then cracks the brickwork or render nearby. A flexible sealant over backing rod is what the joint needs. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs. Ask us for a quote and we will go through it with you.
What you get with us
- Over 20 years’ experience
- Fully insured
- Approved under the ARBOMaster scheme
- Every job guaranteed for a year
See our cost guide and what customers say.
Walls and rooflines in Roxbourne
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Headstone Manor (about 1.8 miles north-east) are a reminder that the area around Roxbourne has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth.
Letting a property close to South Ruislip station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies. If you look after a building such as The Moriah Jewish Day School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Roxbourne is about 1 mile east of Ruislip, in Greater London. If you need external mastic in Roxbourne, it’s easy to get a quote: please ring 0345 464 0079 or drop us an email. We are based in Crawley and cover Greater London, Roxbourne included. 764 places in Greater London are on our list. London is on our list too, about 13 miles from Roxbourne.
Work in HA5, HA2 and HA4 works the same way as everywhere else we cover. You will find streets such as Kings Road, The Avenue and Torbay Road, all of which we cover. We also cover the places around Roxbourne: Rayners Lane (1 mile east), Eastcote (1 mile north-west), North Harrow (1 mile north-east), South Ruislip (1 mile south) and Pinner (1 mile north). Further out, we also cover London (13 miles south-east), City of Westminster (11 miles south-east), Marylebone (11 miles east), Kensington (9 miles south-east), St Pancras (12 miles east) and Shoreditch (14 miles east).
Around Roxbourne
Locally, jobs take us to homes and businesses close to Heathfield School, Pinner High School and Venue 5 pub, among other places. The nearest railway station is South Ruislip station, roughly 1.4 miles south-west of the centre. Nearby you will also find Heath Robinson Museum (1.2 miles north) and St. George's Shopping Centre (1.9 miles east). Open spaces near Roxbourne include Northala Fields and Islip Manor Meadows.
Common questions in Roxbourne
Do you cover Roxbourne for external mastic?
Yes. Our work covers London and the South East, and Roxbourne is part of that. You can ring 0345 464 0079 or send us an email and let us know what needs doing.
Do you work for landlords with property near South Ruislip station?
Yes, rental work is part of what we do. You can call 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before we start.
How long before the joint can be used?
Cure times vary by product and the conditions. We tell you how long to leave it before we go.
Which products do you use?
The product depends on the job: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.
What is backing rod for?
Backing rod goes into deeper joints as a matter of course. It sets the sealant depth and prevents three-sided bonding, so the joint can move.
Do you work for hotels and businesses?
Yes. Hotels, offices and other businesses use us.
Do I have to be there?
It depends on the job. Inside work needs someone to give us access.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. It all has to come out first.