Greater London · England
Colliers Wood External Mastic
We cover Colliers Wood for sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly.
- Joints where the bead has come unstuck
- Old sealant gone brittle and cracked
- Movement joints filled with mortar instead of sealant
How it works
There isn’t much for you to do on the day. Point us to the joints and we will get on with it. The job generally takes a few hours to a few days, depending on the length of joint and the access from start to finish. In Colliers Wood, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Let us know about parking restrictions
- For business premises, tell us about site rules or sign-in
- Tell us about access, such as stairs, a lift or high-level joints
Get a quote
Getting a quote is simple: tell us what needs doing and where, and roughly how big it is. Photos by email help us understand the job.
Related advice
About our external mastic in Colliers Wood
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible exterior sealant takes up that movement where a rigid filler would soon crack. We are often asked to deal with leaking joints around cladding and façade panels and moss and dirt in joints with no sealant left, on render & cladding joints, copings & trims and joints between brick and frames.
London’s terraces and conversions often share walls, gutters and downpipes with their neighbours, so a leaking gutter joint or failed wall joint can affect more than one home. For a flat in Colliers Wood, check the lease for who looks after the outside.
A one-year guarantee comes as standard.
- Location
- Colliers Wood (SW17, SW19, CR4)
- Region
- Greater London
- Guarantee
- One year on every job
- Quote
- A clear price before we start
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Your questions about external mastic in Colliers Wood
Is Colliers Wood in your area for external mastic?
Yes. We work across London and the South East, and Colliers Wood is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job, and we’ll send you a clear quote.
Is parking an issue for external mastic in Colliers Wood?
Parking in Colliers Wood, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Why is there a gap in my brick wall?
A vertical gap in a long brick wall is generally a movement joint. It gives the wall room to move and needs a flexible seal, not mortar.
Do you hold any approvals?
Yes. We’re ARBOMaster approved, the scheme for applicators of Arbo sealants.
Will it make a mess?
We keep the work tidy. Nearby surfaces are protected, and we clear up when we’re done.
What is backing rod for?
Closed-cell backing rod sets the depth of the sealant and stops it sticking to the back of the joint. Then the sealant bonds to two faces and can move.
Do you do commercial work?
Yes. We work in offices, washrooms, hotels and other commercial premises. Working times can be discussed when we quote.
Do you work for landlords and businesses?
Yes. As well as householders, we work for landlords, agents, businesses and hotels.
What we’re called out for in Colliers Wood
Many joints fail because they were sealed too deep or with nothing behind them. If the sealant sticks to the back as well as the sides, it can’t stretch and tears as soon as the joint widens.
These are the problems we’re asked about most:
- Hard, crazed mastic that has stopped moving
- Sealant that has lost its bond to the brick or render
- Rain getting behind render or cladding at a joint
- Joints pointed up with cement by mistake
Rented homes near Tooting station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
What your quote should include
- Whether you can choose the colour
- How long to leave it before use
- What insurance they hold
- How much experience the applicator has
Looking after it afterwards
Simple care keeps the joints in good condition. Our advice:
- Walk round the building once a year and look at the joints
- Act on the first splits you see
- Deal with leaking gutters that soak the joints below
- Never let anyone fill a movement joint with mortar
Look over the joints once a year, ideally after winter. Watch for splits, edges coming away or growth in the joint.
A joint that has stopped moving pushes the movement elsewhere, often as cracks near the joint. Resealing it early helps prevent that.
Nearby places to Colliers Wood
Other services in Colliers Wood
What affects the cost of external mastic
The quote reflects the job in front of us. We look at:
- When we can work, for business premises
- Any mould that needs treating
- The size of the job
- Whether old sealant or filler has to be cut out
We don’t show prices on the website, because the cost depends so much on the job itself. Call for a quick quote.
Helping us quote
To make quoting easier, please include:
- A few photos by email, if you can
- The address or postcode of the job
- Whether it has been sealed before
- What’s wrong with the joints now
Every job is quoted individually, so start by telling us what you need. Just call 0345 464 0079 or drop us an email with the details and send pictures if you have them.
Surface by surface
Render joints
The face of render can be soft, so a low-modulus sealant is kinder to the joint edges. We prime where the product needs it.
Brickwork movement joints
Clay brickwork grows slightly over its life and moves with the weather. That movement goes into the joint, so its sealant has to stay flexible.
Should I try it myself first?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again, so just mention it when you contact us.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
External mastic in Colliers Wood: local notes
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. With historic houses such as Southside House (about 2.8 miles west) nearby, there’s older building stock in the area around Colliers Wood as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
In the older streets around St Nicholas, the joints between older walls, newer extensions and the roofline need a sealant that can move. As a London address, Colliers Wood can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Colliers Wood is about 5 miles south of Brompton, in Greater London. Anywhere in SW17, our applicators can take on external mastic. Colliers Wood is one of 764 places in Greater London where we work for external mastic. There’s also a page for London, about 6 miles away.
We cover every part of the SW17, SW19 and CR4 postcode area for external mastic. We cover properties on Acre Road, Boyd Road and Park Road. Nearby, we also carry out external mastic in Tooting (1 mile north), Tooting Bec (1 mile north), Merton Abbey (1 mile south-west), Furzedown (1 mile north-east) and Eastfields (1 mile south-east). We also work in nearby towns such as London (6 miles north-east), City of Westminster (7 miles north), Marylebone (7 miles north), Kensington (6 miles north), St Pancras (8 miles north) and Shoreditch (8 miles north-east).
What’s near Colliers Wood
Typical jobs here are in homes near Figge's Marsh, Ensham School and The Royal Standard pub and the streets around them. Colliers Wood has its own railway station: Tooting station. Other landmarks nearby include Grove Hospital (0.6 miles north) and Wandle Industrial Museum (1.2 miles south). For a walk, there’s Henman Hill and Myrna Close.
What happens if it’s left?
Running new sealant over the old bead rarely lasts. The new layer cannot bond properly to old, weathered material, so the old joint is cut out fully first. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Why choose Mr Mastic in Colliers Wood
- White, clear, grey or coloured to suit, where the product allows
- 4.9 on Google from 180+ five-star reviews
- Sanitary silicone with an anti-fungal additive in wet areas
- Homes, businesses and hotels
Read our cost guide and customer reviews.