Na h-Eileanan Siar · Scotland
External Mastic in Shawbost
Sealing brickwork movement joints, render, cladding and façade joints for Shawbost, backed by a one-year guarantee. Call for a quick quote.
- Water getting into walls through failed joints
- Brick movement joints where the sealant has split
- Leaking joints around cladding and façade panels
External mastic in Shawbost, done properly
External mastic is a job where short cuts show quickly. Overfilled joints, missing backing rod and sealant laid over old sealant rarely last long. We take the old material out and do it properly. If you have rigid filler in a joint that should flex and movement joints with cracked, split or missing sealant, we can put it right.
Across smaller places in Scotland, stone and harled cottages, farm buildings and newer houses often stand exposed to wind and rain. Gutter joints and wall joints take a battering.
Every job comes with a one-year guarantee, wherever you are in Na h-Eileanan Siar.
- Where
- Shawbost (HS2)
- Wider area
- Na h-Eileanan Siar
- Guarantee
- A year, on every job
- Quotes
- A clear price before work begins
- info@mrmastic.co.uk
- Page updated
- 26 October 2026
What happens on the day
The work is kept neat and contained to the joints we’re treating. Expect the work to take a few hours to a few days, depending on the length of joint and the access, and we tell you how long to leave it before we go. For a place like Shawbost, longer drives are planned in advance. Tell us about tracks, gates, a ferry crossing or anything unusual about getting there.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Move anything stored near the joints
- Mention if the joints have been sealed before
- Mention any tricky access
Get a quote
If you are in Shawbost and need external mastic, send an email to info@mrmastic.co.uk. A short description of the job and where it is helps us quote, and you will get a clear quote before work begins.
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When to call us in Shawbost
A lot of failed joints come down to preparation: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The sealant never bonds properly.
Signs it’s time to call us include:
- Hard, crazed mastic that has stopped moving
- Leaking joints around cladding and façade panels
- Failed seals between different materials
- Rain getting behind render or cladding at a joint
Around Shawbost, as everywhere, external mastic is only as good as the preparation behind it.
Before you book anyone
- When the joint can take water or movement
- Whether all the old sealant comes out first
- Which sealant they’ll use, and why
- Is VAT in the price?
Why act early in Shawbost
A failed movement joint lets water into the wall, behind render and cladding. Resealing early keeps the job to the joint itself, rather than the wall around it. Out of town in Scotland, exposed walls take a lot of weather, and once water gets behind a failed joint, damp in stone or harled walls is slow to dry out.
Some things make a job bigger or smaller: 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.
What you get with us
- We agree the colour with you first
- An ARBOMaster approved applicator
- Rated 4.9 stars on Google
- Sealant colour chosen to suit
Take a look at what affects the cost and what customers say.
Aftercare tips
So the new joints stay in good condition:
- Wash walls gently around the sealant
- Keep soil, plants and ivy away from the joints
- Have failed joints looked at early
- Check the sealant is paintable before painting near it
Do not let soil, plants or ivy build up against the new joints. Anything that holds water against the joint wears it out sooner.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Also near Shawbost
Also in Shawbost
External mastic in Shawbost: local notes
Shawbost is close to the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That’s hard on movement joints and outside wall joints, especially on the side facing the sea. Shawbost is in the west of Scotland, which is wetter than the east, which means movement joints and outside wall joints has to cope with a lot of rain.
Whether the job is in Shawbost itself or nearby, the right material for each joint matters as much as a neat finish.
Shawbost (Gaelic: Siabost) is in Na h-Eileanan Siar. If you need external mastic in Shawbost, it’s easy to get a quote: please send an email to info@mrmastic.co.uk. We cover Na h-Eileanan Siar from our Crawley base. We cover 87 towns and villages across Na h-Eileanan Siar.
Work in HS2 works the same way as everywhere else we cover. That includes homes and businesses on Rathad Ghrinnibhat, Cnoc a Charnain and Sraid na H-Eaglaise and the roads around them. If you are just outside Shawbost, we cover Bragar (2 miles north-east), Na Gearrannan (4 miles south-west), Carloway (4 miles south-west), Barabhas (7 miles east) and West Side (7 miles east). Remote and island addresses need a little more planning, so please mention your location when you drop us a line at info@mrmastic.co.uk.
What’s near Shawbost
Well-known places in the area include Shawbost Folk Museum (0.7 miles north-east). Open spaces near Shawbost include Loch a' Bhaile.
What affects the quote in Shawbost
Your quote is based on your job. We take into account:
- Whether old sealant or filler has to be cut out
- Any mould that needs treating
- How many rooms, windows or areas are involved
- Any working-time requirements on site
What you pay reflects the work, not a rough estimate. That is why we ask about the job first.
Asking for a quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- Roughly how big the job is
- Where the property is
- The problem you’ve noticed
- If someone has resealed it before
There’s no standard price list. Instead, your job gets its own clear quote. To arrange one, email us at info@mrmastic.co.uk.
Should I try it myself first?
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions.
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.
Questions from Shawbost
Do you cover smaller places like Shawbost?
Yes, we do. Our work covers the whole of Scotland, islands included, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Is Shawbost in your area for external mastic?
Yes. Our work covers the whole of Scotland, and Shawbost is part of that. Just drop us a line at info@mrmastic.co.uk with a few details of the job.
Why is there a gap in my brick wall?
Brickwork, render and cladding all move a little, so long walls have planned gaps to take that movement. The gap is sealed with a flexible sealant over backing rod.
Is it OK to fill a movement joint with cement?
No. A mortar-filled joint cannot move, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
I rent my home. Can I book you?
We can work for tenants, landlords or agents. Get your landlord’s agreement first.
Do the sealants smell?
Sometimes, a little. Any smell clears as the sealant cures.
What does external mastic cost?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote and we’ll talk you through it.
What colours does the sealant come in?
We aim for a joint that suits the wall rather than one that jumps out. Colour is agreed with you before we begin, matched as closely as the range allows.
Different surfaces, different methods
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. We reseal them with a low-modulus sealant over backing rod coloured to suit the wall.
Copings and trims
Coping and trim joints face rain and sun head on. We reseal them with an exterior sealant suited to the material.