Na h-Eileanan Siar · Scotland
External Mastic in Grimsay
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Grimsay and across Na h-Eileanan Siar. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Weeds or debris growing in open joints
- Movement joints with cracked, split or missing sealant
- Gaps where render, brick and frames meet
External mastic in Grimsay
Getting the depth right is half the job. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, leaving it bonded to two faces so it can move with the wall. Typical jobs include failed sealant between panels on a façade and weathered mastic that no longer stretches, on copings & trims, render & cladding joints and façade panels.
Stone walls need a stone-friendly sealant, as acetoxy products can attack some stone. Newer houses need their movement joints and roofline trims kept sound.
Big or small, you get the same 12-month guarantee in Grimsay and across Na h-Eileanan Siar.
- Place
- Grimsay (HS7)
- Region
- Na h-Eileanan Siar
- Cover
- One year on every job
- Price
- Quoted before any work starts
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
Different surfaces, different methods
Render joints
Render has movement joints and stop beads that need sealing. They’re resealed in a sealant that suits the render.
Concrete and blockwork
Big joints in concrete need careful depth control. Backing rod sized to the joint sets it so the sealant isn’t too deep.
Towns and villages near Grimsay
Also in Grimsay
For landlords and businesses
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Can I do it myself?
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
Honest limits
We’d rather tell you now than do work that won’t last, so here’s what sealant cannot put right:
- Loose or hollow render, which needs re-rendering
- Adding movement joints to masonry that has none
- Damp that is not coming from the joint
Not sure which it is? You can drop us a line at info@mrmastic.co.uk and we will tell you honestly.
What we seal
- Render & cladding joints
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
- Façade panels
Grimsay questions
Will you come out to Grimsay?
Yes, Grimsay is covered. We work across all of Scotland, islands included, and smaller places are part of that. Longer journeys are simply planned in advance.
Do you cover Grimsay for external mastic?
Yes, Grimsay is within the area we cover. Our work covers the whole of Scotland. Just email us at info@mrmastic.co.uk with a few details of the job.
Is there a guarantee?
Yes, for a year. If anything is not right with the work within the year, let us know and we will sort it.
Should I try DIY first?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Where are you based?
Our base is Crawley. We work across South East England, London and Scotland.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator, and we’re fully insured.
Why do you put foam in the joint first?
Backing rod goes into deeper joints as a matter of course. It controls the depth and stops the sealant bonding to the back so the bead can stretch.
Can tenants book the work?
Of course. Ask your landlord first, and we can send them the quote if that helps.
Grimsay buildings and the weather
Grimsay is within about 1 mile of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That is hard on movement joints and outside wall joints, especially on the side facing the sea. Plenty of Scottish homes have harled walls, and joints where harling meets other materials need a sealant that can grip and flex.
Whether the job is in Grimsay itself or nearby, the right material for each joint matters as much as a neat finish.
Grimsay (Gaelic: Griomasaigh) is in Na h-Eileanan Siar. Across the HS7 area, our applicators can take on external mastic. Across Na h-Eileanan Siar, we cover 87 places, and Grimsay is one of them.
Work in HS7 is quoted and booked the same way as anywhere else. You will find Grimsay on the B891, so it’s easy for us to get to with everything needed for external mastic. We also cover the places around Grimsay: Creag Ghoraidh (2 miles west), Geirinis (5 miles south-west), Balivanich (5 miles north-west), Baile a' Mhanaich (6 miles north-west) and Locheport (10 miles north). Remote and island addresses need a little more planning, so tell us where you are when you ask for a quote.
Near you in Grimsay
Nearby you’ll also find Museum nan Eilean Lionacleit (3.1 miles west) and Borve Castle (3.7 miles north-west). Green spaces nearby include Loch Langavat and Stiaraval.
What happens on the day
All our tools and materials come with us in the van. After a quick look at the joints together, we protect the area and start. Most jobs take a few hours for a handful of joints, longer for a whole elevation. In smaller Scottish places, parking is generally less of an issue than access and distance. Tell us how to find the property and how to reach the work, and the visit is planned around that.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Before we arrive
- Keep pets and children clear of the area while we work
- Try not to wet indoor joints just before the visit
- Mention any leaks or damp you’ve noticed
Get a quote
To get a quote, drop us a line at info@mrmastic.co.uk and tell us where the job is and what the problem looks like. You’ll have a clear quote before we start.
Related advice
How we quote for external mastic
Your quote is based on your job. We take into account:
- The type of sealant required
- Whether there’s mould to deal with
- When we can work, for business premises
- The number of rooms or windows
The cost depends on how much there is to do, how hard the old material is to remove and how easy the joints are to reach. You will have a clear quote before any work starts, so you know where you stand.
Helping us quote
Photos help, but a description is a good start. Please mention:
- Any access issues, like height or stairs
- If it’s domestic, commercial or a hotel
- A few photos by email, if you can
- The address or postcode of the job
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will explain how we’d tackle it. When it suits you, send an email to info@mrmastic.co.uk.
What we’re called out for in Grimsay
A lot of failed joints come down to preparation: dusty or wet faces, no primer where one was needed, or old sealant left in. The sealant never bonds properly.
Any of these means the joints need attention:
- Sealant that has lost its bond to the brick or render
- Cracked joints where brick meets render or frames
- Brick movement joints where the sealant has split
- Weeds or debris growing in open joints
Around Grimsay, as everywhere, external mastic is only as good as the preparation behind it.
Questions to ask before booking
- How long to leave it before use
- How the joint is cleaned and prepared
- Which sealant they’ll use, and why
- How much experience the applicator has