Scottish Borders · Scotland
External Mastic in St Boswells
Professional external mastic in and around St Boswells, with old sealant always removed completely and a 12-month guarantee.
- Joints with sealant missing in places
- Panel joints letting water in
- Gaps where render, brick and frames meet
Different surfaces, different methods
Cladding and façade panels
Where a cladding system has its own specified sealant, we follow it, or one the system allows. Tell us what the building has when you get in touch.
Render joints
Rendered walls have joints at beads, openings and changes of material. They’re resealed in a sealant that suits the render.
External mastic for homes and businesses in St Boswells
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. The colour is chosen to suit the brick or render. We work on façade panels, brickwork movement joints and render & cladding joints, and people most often call us about cracked joints where brick meets render or frames and weeds or debris growing in open joints.
Older stone buildings need a sealant that suits the stone, not an acetoxy product that can mark or attack it. On newer homes, the movement joints and roofline trims are what need watching.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- St Boswells (TD6)
- Region
- Scottish Borders
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
Honest limits
We will always be straight with you, so here’s what new sealant won’t do:
- Subsidence or other structural problems
- Rising or penetrating damp from elsewhere in the wall
- Cracking across the wall rather than at a joint
If in doubt, drop us a line at info@mrmastic.co.uk and we’ll say what we think.
Joints and surfaces we work on
- Brickwork movement joints
- Joints between brick and frames
- Façade panels
- Render & cladding joints
- Copings & trims
- Concrete & block
Looking after it afterwards
A little care helps the new joints last. Our advice:
- Have failed joints looked at early
- Tell anyone working on the walls about the movement joints
- Keep water from gutters off the wall
- Look over the joints every year, ideally after winter
Keep pressure washers away from the sealant. A strong jet can damage the edges of the bead and let water in behind.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established so early resealing is worth it.
What happens on the day
We bring everything the job needs with us, so you don’t need to buy or prepare anything. After a quick look at the joints together, we protect the area and start. Most jobs take a few hours to a few days, depending on the length of joint and the access. Somewhere like St Boswells may be a longer drive, and the journey is planned ahead. Tell us about tracks, gates, a ferry crossing or anything unusual about getting there.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
How to prepare
- Mention any tricky access
- Mention if the joints have been sealed before
- Where the joints are inside, avoid wetting them before we arrive
Get a quote
Asking for a quote is easy: let us know what needs doing and where. Photos by email help us understand the job, and we’ll take it from there.
Advice
Nearby places to St Boswells
More services for St Boswells
Leave it or put it right?
An open joint keeps letting water into the wall with every downpour. Wet masonry is more easily damaged by frost around the joint, so the problem grows beyond the joint itself. Exposed walls in smaller Scottish places take a lot of wind and rain, and once water gets behind a failed joint, damp in stone or harled walls is slow to dry out.
Doing several joints on one visit is generally more efficient than separate visits. You will get one clear quote for the whole job.
Why book with us
- Arbo and Everbuild products
- Full insurance on every job
- An ARBOMaster approved applicator
- A choice of colours where the product allows
See what affects the cost or our reviews.
For landlords and businesses
For anyone letting property in or around St Boswells, several properties can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
From a single let to a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Signs you need external mastic in St Boswells
Sometimes a movement joint was filled with mortar or a rigid filler. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Keep an eye out for these signs:
- Failed seals between different materials
- Leaking joints around cladding and façade panels
- Joints with sealant missing in places
- Plants rooting in failed movement joints
If you live in an older home near St Boswells Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
What your quote should include
- When the joint can take water or movement
- Is the old sealant removed completely?
- What preparation is included
- How much experience the applicator has
Questions from St Boswells
Do you cover St Boswells for external mastic?
Yes. Our work covers the whole of Scotland, and St Boswells is part of that. You can email us at info@mrmastic.co.uk and tell us what needs doing.
Is St Boswells within the area you cover?
Yes, we do. We work across all of Scotland, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Are you fully insured?
Yes. We’re fully insured, with over 20 years’ experience in sealant work.
Do I have to be there?
It depends on the job. Inside work needs someone to give us access, while outside work can sometimes be arranged differently.
I’m a tenant. Can you help?
We can work for tenants, landlords or agents. Just make sure your landlord agrees.
Do you work for letting agents?
Yes. We work for homeowners, landlords, letting agents, businesses and hotels across the Scottish Borders.
Is it OK to fill a movement joint with cement?
No. Cement or mortar can’t stretch and the joint fails. If it has already been filled, we can generally cut it out and reseal it.
Is there a guarantee?
Yes. Each job is guaranteed for twelve months, wherever you are.
Walls and rooflines in St Boswells
Private landlords in Scotland must meet the Repairing Standard, which includes keeping a home wind and watertight, and sound outside sealant is part of that. Harled (roughcast) walls are common in Scotland, and where harling meets frames, pipes and other materials, the joint needs a flexible sealant that grips a rough surface.
Around St Boswells, as everywhere, external mastic is only as good as the preparation behind it.
St Boswells is about 7 miles south-east of Galashiels, in the Scottish Borders. Homes, rented property, offices and hotels in St Boswells can book us for external mastic. Every job comes with our one-year guarantee. Our area takes in 89 places across the Scottish Borders, from the larger towns to small villages. We also work in Edinburgh, about 34 miles from St Boswells.
We work across the TD6 postcode area for external mastic and the streets around it. Whether your property is on Main Street, Southfield and Weirgate Avenue or a nearby road, we can help. St Boswells sits on or near the A699, so getting to you is simple. Nearby, we also carry out external mastic in Greycrook (1 mile south-east), Maxton (1 mile south-east), Newtown St Boswells (1 mile west), Bowden (3 miles west) and Newstead (3 miles north-west). Larger places within reach include Galashiels (7 miles north-west), Hawick (12 miles south-west), Kelso (8 miles east), Selkirk (8 miles west), Jedburgh (7 miles south-east) and Wilton (12 miles south-west).
What’s near St Boswells
Other landmarks nearby include Commendators House Museum (3.6 miles north-west) and Castle Holydean (3.7 miles west). The countryside around St Boswells includes Eildon Hill North and Bemersyde Moss.