Greater London · England
Roxeth External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homeowners, landlords and businesses in Roxeth. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Weathered mastic that no longer stretches
- Leaking joints around cladding and façade panels
- Joints where the bead has come unstuck
Landlord and commercial work in Roxeth
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will quote.
Housing providers, facilities teams and property managers book us too in Roxeth and across Greater London. We can quote a run of properties together, and we’re fully insured for the work.
About our external mastic in Roxeth
Low-level joints can usually be done from the ground. Where joints are higher up, tell us about the building when you get in touch and we will confirm what’s needed to reach them safely. If you’re dealing with old sealant gone brittle and cracked and gaps where render, brick and frames meet, we can put it right, on façade panels, joints between brick and frames and brickwork movement joints alike.
Modern London flats rely on sealed movement joints and cladding joints. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall.
The work is guaranteed for twelve months. If something isn’t right with it in that time, tell us and we will put it right.
- Location
- Roxeth (HA2, HA1, UB5)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Should I try it myself first?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it does not work out, we can still put it right.
When something else is needed
We’ll always be straight with you, so here’s what sealant can’t fix:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Damp that is not coming from the joint
- Render that is blown, hollow or coming away
Not sure which it is? You can call 0345 464 0079 or send us an email and we will tell you honestly.
Where we work in Roxeth
- Joints between brick and frames
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Copings & trims
- Concrete & block
What external mastic looks like in Roxeth
Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking.
For landlords with property near Sudbury Hill Harrow station, split movement joints are easy to miss on a rental until damp shows inside. Homes close to Christ Church include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant.
Roxeth is about 1 mile south of Harrow, in Greater London. We provide external mastic to homes and businesses in Roxeth and the surrounding area. Across Greater London, we cover 764 places, and Roxeth is one of them. You can also see our page for London, about 12 miles away.
We cover every part of HA2, HA1 and UB5 for external mastic and the streets around it. Local streets include Lower Road, Grange Road and Dudley Road, and we cover them all. If you are just outside Roxeth, we cover South Harrow (1 mile south-west), Harrow (1 mile north), Harrow on the Hill (1 mile east), Northwick Park (1 mile north-east) and Rayners Lane (1 mile west). Larger places within reach include London (12 miles south-east), City of Westminster (9 miles south-east), Marylebone (9 miles east), Kensington (8 miles south-east), St Pancras (10 miles east) and Shoreditch (12 miles east).
Near you in Roxeth
In Roxeth, that means homes and buildings near The White Horse pub, Orley Farm School and Northwick Park, among other places. The closest station to Roxeth is Sudbury Hill Harrow station, roughly 0.8 miles south-east. A little further out are Clementine Churchill Hospital (0.7 miles east) and Kodak Museum (1.7 miles north). Green spaces nearby include Northala Fields and Perivale Wood.
What affects the cost of external mastic
We quote each job individually. This is what makes a difference:
- The size of the job
- Whether old sealant or filler has to be cut out
- Which sealant suits the joint
- Whether there’s mould to deal with
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Helping us quote
Photos help, but a description is a good start. Try to tell us:
- Where the property is
- A few photos by email, if you can
- Any previous sealing or DIY work
- Roughly how big the job is
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will talk you through what we’d do. Whenever you are ready, phone 0345 464 0079 or email us.
Your questions about external mastic in Roxeth
Can parking be tricky for a visit in Roxeth?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
I let a flat near Sudbury Hill Harrow station. Can you help?
Yes. We work for landlords and agents as well as homeowners. You can ring 0345 464 0079 or email us with the details for a clear quote.
Does someone need to be in?
That depends on where the joints are. Inside work needs someone to give us access, while outside work can sometimes be arranged differently.
Can I do it myself?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
Can you reach joints on upper floors?
It depends on the building. Where joints can be reached safely, we’ll do them. Give us some details and we’ll confirm the access.
Do you seal joints where cladding meets other materials?
Yes. Different materials move at different rates, so the joint between them must be flexible. We choose one that suits both surfaces.
Is it OK to seal over old sealant?
No, it will not last. It may look fine at first, but the new layer lifts away from the old one. The old sealant has to come out completely.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, the approved applicator scheme for Arbo sealants.
Nearby places to Roxeth
What else we do in Roxeth
What we are called out for in Roxeth
Sometimes a movement joint was filled with mortar or a rigid filler by mistake. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
If you can see any of these, it’s time to have the joints looked at:
- Plants rooting in failed movement joints
- Sealant pulling away from one side of the joint
- Cracked joints where brick meets render or frames
- Movement joints filled with mortar instead of sealant
Roxeth is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Before you book anyone
- What happens if they find a problem under the old sealant
- When the joint can take water or movement
- How the surfaces are prepared before sealing
- Are they insured?
Why it’s worth doing now in Roxeth
Done well, a resealed joint is a neat, straight line that suits the wall. A rushed bead with no backing looks untidy and doesn’t last, so it pays to do it properly once. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. The price is agreed before we begin.
What you get with us
- Over 20 years’ experience
- A choice of colours where the product allows
- Sanitary silicone with an anti-fungal additive in wet areas
- 12-month guarantee on every job
Read what affects the cost and customer reviews.
How it works
We work through the job in order: protect, prepare, seal, tidy. Typically it takes a few hours to a few days, depending on the length of joint and the access, and the area is left clean. In Roxeth, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs 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.
Getting ready for the visit
- Let us know about parking restrictions
- For business premises, tell us about site rules or sign-in
- For indoor joints, keep the area dry beforehand if you can
Getting a quote
Need a quote? Please phone 0345 464 0079 or email us with a few details. You will know what we plan to do, and what it will cost, before any work begins.