Na h-Eileanan Siar · Scotland
External Mastic in Back
External mastic for Back, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Rain getting behind render or cladding at a joint
- Gaps where render, brick and frames meet
- Weathered mastic that no longer stretches
External mastic in Back, done properly
Low-level joints can normally be done from the ground. For joints higher up, give us some details of the building and we’ll confirm what access is needed. If you’re dealing with joints with sealant missing in places and gaps where render, brick and frames meet, we can put it right, on render & cladding joints, façade panels and concrete & block alike.
External sealant needs dry surfaces, so outdoor work around Back is planned around the weather, and longer journeys are planned in advance. Tell us how to reach each wall, gutter and roofline.
There’s a 12-month guarantee on every job, whatever its size.
- Where
- Back (HS2)
- Wider area
- Na h-Eileanan Siar
- Cover
- A year, on every job
- Quotes
- A clear price before we start
- info@mrmastic.co.uk
- Page updated
- 26 October 2026
When to call us in Back
Buildings move more than people expect. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. All of that ends up in the joint sealant.
Any of these means the joints need attention:
- Movement joints filled with mortar instead of sealant
- Plants rooting in failed movement joints
- Joints with sealant missing in places
- Damp patches traced to an open external joint
In and around Back, as anywhere, good external mastic starts with a clean, dry, properly prepared joint.
What your quote should include
- How the surfaces are prepared before sealing
- Whether the sealant suits the joint
- Whether all the old sealant comes out first
- Who turns up on the day
How it works
There’s no need to move everything out, just the space around the work. Everything nearby is protected, and the work takes a few hours for a handful of joints, longer for a whole elevation for a typical job. Somewhere like Back may be a longer drive, and the journey is planned ahead. Mention tracks, gates, ferries or anything else about the route.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- Old sealant and any debris are cut and raked out.
- Both sides are cleaned back to sound material and primed if needed.
- 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.
How to prepare
- Mention any sign-in or site rules at work premises
- Let us know if you’ve seen damp or leaks
- Clear the area around the work
Get a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email pictures if that is easy.
Related advice
Nearby places to Back
Other services in Back
What the job involves on each surface
Joints between dissimilar materials
Where a frame or panel meets masonry, water often finds a way in. We cut out the old sealant and reseal with a product suited to both surfaces.
Concrete and blockwork
Concrete faces can be dusty and porous, so preparation is key. A primer goes on where the product requires one.
Why act early in Back
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. Around Back, water from a failed joint in an older stone home can soak into timber and plaster, which is a far bigger job than the sealant.
Combining jobs into one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. We’ll send you a clear quote for the lot.
What you get with us
- You choose the colour before work begins
- Trusted Arbo and Everbuild sealants
- We leave the area clean and tidy
- White, clear, grey or coloured to suit, where the product allows
Take a look at what affects the cost and our reviews.
What sealant work can’t fix
To be straight with you, some problems need a different trade:
- Failed render or damaged cladding panels
- Damp that isn’t coming from the joint
- Cracking across the wall rather than at a joint
If you’re not sure, just send an email to info@mrmastic.co.uk and we’ll give you a straight answer.
Surfaces we seal
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
- Brickwork movement joints
- Copings & trims
- Façade panels
Should I try it myself first?
If you’ve already had a go yourself, that is fine. We cut it out and start again, so tell us about it when you ask for a quote.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and getting the depth right matters as much as the look.
FAQs for Back
Will you come out to Back?
Yes, smaller places are covered as well as towns. We work across all of Scotland, including the islands, where work is planned around ferry crossings. Let us know about access, parking and anything unusual about getting there when you book.
Do you cover Back for external mastic?
Yes. Our work covers the whole of Scotland, and Back is part of that. Just send an email to info@mrmastic.co.uk with a few details of the job.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages to suit the site.
Do I have to be there?
If the work is inside, we need someone to let us in. After that, you can carry on with your day.
How long will you be here?
As a guide, most jobs take a few hours for a handful of joints, longer for a whole elevation. Larger jobs naturally take longer, and we will say how long yours will take.
Do you work for landlords and businesses?
Yes. Domestic, commercial and hotel work are all part of what we do, and we’re fully insured.
Should I point up the gap in my brickwork?
No, not if it’s a movement joint. Filling it with mortar defeats its purpose, and the wall may crack nearby. A flexible sealant is the right fill.
I rent my home. Can I book you?
Of course. Check with your landlord; we can send the quote to them too.
External mastic in Back: local notes
Back is close to the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. That’s hard on movement joints and outside wall joints, especially on the side facing the sea. Work on the islands has to be planned around ferry crossings and the weather, so give us as much notice as you can.
Whether the job is in Back itself or nearby, the right material for each joint matters as much as a neat finish.
Back is about 6 miles north-east of Stornoway, in Na h-Eileanan Siar. Every kind of property in Back is covered for external mastic, old or new, large or small. Every job comes with our 12-month guarantee. Our area takes in 87 places across Na h-Eileanan Siar, from the larger towns to small villages.
Jobs for external mastic in HS2 is quoted and booked the same way as anywhere else. You’ll find streets such as Broadbay View, Rathad na Sgoile and Sraid na H-Eaglaise. Close by, we work in Sulaisiadar (5 miles south-east), Garrabost (5 miles south-east), Na h-Eileanan an Iar (5 miles south), Knock (5 miles south) and Aiginis (5 miles south). Island and remote addresses take a little more planning, so please mention your location when you email us at info@mrmastic.co.uk.
Around Back
Nearby you will also find Western Isles Hospital (5.4 miles south-west). Not far away are Loch Langavat.
How we quote for external mastic
For a quick quote, just ask. The main things that affect it are:
- Whether old sealant or filler has to be cut out
- Which sealant suits the joint
- Any working-time requirements on site
- How many rooms, windows or areas are involved
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all play a part.
Helping us quote
To make quoting easier, please include:
- Roughly how big the job is
- Photos by email, if that’s easy
- What’s wrong with the joints now
- How we’d reach the joints
Want a quote for external mastic? Please send an email to info@mrmastic.co.uk and tell us about the job. You’ll know what we plan to do, and what it will cost, before any work begins.