Na h-Eileanan Siar · Scotland
Sand mastic for sash & case windows in Back, Na h-Eileanan Siar
We cover Back for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Silicone on a period window that looks wrong
- Old cement repairs round a window that have failed
- Draughts and rain around sash boxes
Sand mastic in Back, done properly
Sand mastic is the traditional way to point the gap between a timber window frame and the stone or brick around it. It’s a mix of sand and a linseed-oil-based binder, applied by hand. On period homes, it looks right where silicone wouldn’t. Common call-outs are for draughts and rain around sash boxes and crumbling sand mastic round a window, across tenement windows, brick reveals and sash and case windows.
Outdoor sealant needs a dry surface, so window work around Back is planned around the weather, and longer journeys are planned in advance. Let us know about access to every frame, including any upstairs.
You are covered for a year from the day we finish. If there’s a problem with it, please email us at info@mrmastic.co.uk.
- Where
- Back (HS2)
- Region
- Na h-Eileanan Siar
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- info@mrmastic.co.uk
- Updated
- 26 October 2026
What happens if it’s left?
A silicone bead can be quicker, but on period stone or brick it often looks out of place. Sand mastic suits the building and blends with the stone or brick. When the nearest tradesperson is a drive away, it’s tempting to leave a small leak, but water through a failed joint keeps working away until it’s fixed.
Doing several joints on one visit generally makes better use of the time than several visits. We will give you a clear quote for the lot.
What you get with us
- Fully insured
- Anti-fungal silicone where joints get wet
- Rated 4.9 stars on Google
- An ARBOMaster approved applicator
See what affects the cost and what customers say.
Also in Back
Can I do it myself?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
What we do, step by step
We keep the work tidy and contained to the area we’re working on, so you can carry on as normal. Expect the work to take a few hours per window, depending on the condition of the joints. In smaller Scottish places, parking is usually less of an issue than access and distance. Let us know how to find you and how to reach the joints.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Getting ready for the visit
- Clear items away from the joints we are working on
- For business premises, tell us about site rules or sign-in
- Mention any leaks or damp you’ve noticed
Getting a quote
We quote each job on its own. Just drop us a line at info@mrmastic.co.uk with the details.
Read more
Back questions
Does the coastal weather in Back affect outside sealant?
Near the coast, wind-driven rain and, nearer the shore, salt air make outside sealant work harder. The right product, a clean joint and the right depth all help it cope.
Will you come out to Back?
Yes, we do. We work across all of Scotland, islands included, and smaller places are part of that. Longer journeys are simply planned in advance.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, which is run for the Arbo sealant brand.
Is it possible to paint over sand mastic?
The usual advice is to leave sand mastic unpainted. Ask us before you decorate around it and we will advise.
How long does sand mastic take to go off?
It takes a while. The skin forms first, and the full set comes later, and we will tell you what to expect.
Can you do several jobs on one visit?
Yes. Tell us about everything you’d like done.
Is it worth trying it myself?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional.
How long does sand mastic take?
As a guide, most jobs take a few hours for a single window, longer for several. Bigger jobs take longer.
What affects the cost of sand mastic
There’s no set price list, because jobs vary so much. What we look at:
- Mould in or behind the old joints
- How many areas need sealing
- How much there is to do
- Whether the work is at height
Leaving a failed joint usually makes the job bigger, not smaller, because water and mould keep working on it. If you’re unsure, send an email to info@mrmastic.co.uk for an honest opinion and a quote.
What we need to know
Photos by email are helpful but not essential. Try to tell us:
- How we’d reach the joints
- Whether it has been sealed before
- Roughly how big the job is
- The type of property
There’s no standard price list, because every job is different. Instead, your job gets its own clear quote. To arrange one, send an email to info@mrmastic.co.uk.
Frames and glazing around Back
Back is within about 1 mile of the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. Both are hard on the mastic around older windows and doors, which can dry out and crack sooner where a building faces the weather. Back is in the west of Scotland, which is wetter than the east, so there’s plenty of rain for the mastic around older windows and doors to keep out.
For jobs in and around Back, choosing the right material for each joint is as important as a tidy finish.
Back is about 6 miles north-east of Stornoway, in Na h-Eileanan Siar. Jobs in Back get the same care as everywhere else we work: old sealant removed completely, careful preparation and a one-year guarantee. Across Na h-Eileanan Siar, we cover 87 places, and Back is one of them.
Work in HS2 is quoted and booked the same way as anywhere else. Local streets include Broadbay View, Rathad na Sgoile and Sraid na H-Eaglaise, all of which we cover. If you are just outside Back, we cover 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). 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.
Local landmarks in Back
Other landmarks nearby include Western Isles Hospital (5.4 miles south-west). The countryside around Back includes Loch Langavat.
Landlord and commercial work in Back
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
Common problems we fix in Back
Most of it is simply age. Even well-laid mastic needs renewing in time, depending on exposure and upkeep.
It’s worth asking for a quote if you see:
- Cement or filler used on old window joints that has cracked
- Gaps between timber frames and stone or brick
- A silicone bead on a sash window that spoils the look
- Cracked mastic round a front door frame
In and around Back, as anywhere, good sand mastic starts with a clean, dry, properly prepared joint.
Before booking anyone
- Whether VAT is included
- How the joint is cleaned and prepared
- When the joint can take water or movement
- What product goes in the joint
How the job changes by surface
Tenement and terrace windows
Windows above ground floor need the right access. Tell us the height and we will confirm what’s needed.
Sash and case windows
Most of our sand mastic work is on sash windows. We renew the mastic round each box.