Scottish Borders · Scotland
Duns External Mastic
Movement joints in Duns need attention? We remove the old material, prepare the joints and seal them properly, and the work is guaranteed for a year.
- Leaking joints around cladding and façade panels
- Cracked joints where brick meets render or frames
- Old sealant gone brittle and cracked
Leave it or put it right?
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That matters on brick, render and concrete, which can be weaker at the face. Too stiff a sealant can pull at the edges and break them. Around Duns, water from a failed joint in an older stone home can soak into timber and plaster.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Why us?
- 4.9 on Google from 180+ five-star reviews
- A 12-month guarantee on all work
- A choice of colours where the product allows
- Sealant colour chosen to suit
Take a look at what affects the cost or what customers say.
How we handle external mastic in Duns
Movement joints let brickwork, render and cladding expand and shrink without cracking. The sealant in it has to stretch and squeeze for years, so once it splits or hardens, the joint stops working and water gets in. If you are dealing with leaking joints around cladding and façade panels and rain getting behind render or cladding at a joint, we can help.
External sealant needs dry surfaces, so outdoor work around Duns is planned around the weather. Let us know about access to every wall and roofline.
All of our work is guaranteed for twelve months, and the guarantee is the same wherever you are.
- Place
- Duns (TD11)
- Wider area
- Scottish Borders
- Cover
- A year, on every job
- Quotes
- A clear price before work begins
- info@mrmastic.co.uk
- Page updated
- 26 October 2026
Work for landlords, hotels and businesses
Landlords and letting agents in Duns can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
What happens on the day
On the day, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before work begins. The work normally takes anything from a few hours to several days, depending on the building. Outdoor work around Duns depends on the weather, as sealant needs a dry surface, so an outdoor job can move if the forecast changes. Work indoors is not affected.
- 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.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Preparing for the visit
- For indoor joints, keep the area dry beforehand if you can
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us about any water getting in
How to get a quote
Asking for a quote is easy: tell us what needs doing and where and its rough size. Photos by email help us understand the job.
Read more
What the job involves on each surface
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and protects the render itself.
Cladding and façade panels
Panels heat up and cool down quickly, so the joints work hard every day. We choose the product to suit.
When to call us in Duns
UV, rain and frost all age exterior sealant. In time it goes hard, crazes on the surface and stops stretching, so the joint eventually tears or comes away from one side.
The problems people normally mention when they call include:
- Weathered mastic that no longer stretches
- Sealant pulling away from one side of the joint
- Movement joints filled with mortar instead of sealant
- Failed seals between different materials
In the older streets around Old Parish Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
Before you book anyone
- Whether they seal over old material or remove it
- How the colour is chosen
- How hidden problems are handled
- How the surfaces are prepared before sealing
Also in Duns
Questions from Duns
What guarantee comes with external mastic in Duns?
Every job comes with our one-year guarantee, wherever it is. We’re fully insured, and an ARBOMaster approved applicator.
Is Duns within the area you cover?
Yes, we do. Our work covers the whole of Scotland, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Is it OK to seal over old sealant?
No, because it fails. We remove every bit of old sealant first, so the new joint bonds to clean surfaces.
Do you hold any approvals?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we’re part of it.
What’s an expansion joint in brickwork?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It should be filled with flexible sealant, never mortar.
Will there be a smell?
There can be a smell while the sealant cures, but it fades. Opening a window helps.
Why do you put foam in the joint first?
We fit closed-cell backing rod wherever the joint depth needs controlling. It controls the depth and stops the sealant bonding to the back so the bead can stretch.
Can I do it myself?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs.
Aftercare tips
Simple care keeps the joints in good condition. We recommend:
- Never let anyone fill a movement joint with mortar
- Walk round the building once a year and look at the joints
- Deal with leaking gutters that soak the joints below
- Keep soil, plants and ivy away from the joints
Avoid pressure-washing straight into the joints. 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.
When something else is needed
We’d rather tell you now than do work that will not last, so here’s what sealant cannot put right:
- Structural movement, which needs a surveyor or engineer
- Walls that need new movement joints cut into them
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
Not sure which it is? You can send an email to info@mrmastic.co.uk and we will tell you honestly before you book.
Where we work in Duns
- Brickwork movement joints
- Joints between brick and frames
- Concrete & block
- Copings & trims
- Façade panels
- Render & cladding joints
Walls and rooflines in Duns
Under the Repairing Standard, private landlords in Scotland have to keep homes wind and watertight, and sound outside sealant is part of that. Harled (roughcast) walls are common in Scotland, and joints where harling meets other materials need a sealant that can grip and flex.
Managing a site like Berwickshire High School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Duns is in the Scottish Borders. Jobs in Duns get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Duns is one of 89 places in the Scottish Borders where we work for external mastic. There’s also a page for Edinburgh, about 35 miles away.
Postcode districts we cover here for external mastic: TD11. We cover properties on Market Square, Station Road and Murray Crescent and the roads around them. Being close to the A6105 and A6112, Duns is simple for us to get to for external mastic. Close by, we work in Clockmill (1 mile west), Gavinton (1 mile south-west), Preston (2 miles north), Swinton (5 miles south-east) and Chirnside (5 miles east). As one of the bigger places in the Scottish Borders, Duns has every kind of property, from flats to offices.
Landmarks near Duns
Around Duns, our work takes us to homes and buildings near The Royal Bar. A little further out are Knoll Hospital (under half a mile south) and Jim Clark Motorsport Museum (under half a mile west). Open spaces near Duns include Duns Law and Duns Castle nature reserve.