Na h-Eileanan Siar · Scotland
Sand mastic for sash & case windows in Bàgh a'Chaisteil, Na h-Eileanan Siar
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Bàgh a'Chaisteil and across Na h-Eileanan Siar. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Mastic dropping out of the joint
- Open joints round the window box
- Failed mastic on an exposed elevation
About our sand mastic in Bàgh a'Chaisteil
Silicone on a period window often looks wrong and does not suit the building. Sand mastic gives a finish that matches the age of the house, and we can replace one with the other. We work on tenement windows, sash and case windows and period & listed homes, and people most often call us about gaps where the frame meets the masonry and weathered mastic on the most exposed windows.
Older stone-built homes in Scotland often have sash and case or timber windows set in stone. Those suit a traditional sand mastic or a neutral-cure sealant, not an acetoxy silicone that can attack some stone.
Every job comes with our one-year guarantee, wherever you are in Na h-Eileanan Siar.
- Place
- Bàgh a'Chaisteil (HS9)
- Wider area
- Na h-Eileanan Siar
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
How to look after the new joints
A little care helps the new joints last. Our advice:
- Go gently near the mastic when preparing windows
- Don’t run silicone over sand mastic
- Do not paint over the new mastic
- Sort the mastic before the decorators arrive
Avoid painting over the new mastic, which is the traditional advice. Ask us before any decorating around it.
Renewing mastic before redecorating saves doing it twice. Painting over failed mastic hides the problem for a while.
Should I try it myself first?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
What affects the quote in Bàgh a'Chaisteil
There’s no set price list. The quote depends on:
- Whether old sealant or filler has to be cut out
- Mould in or behind the old joints
- Access and height
- The type of sealant required
The cost depends on the size of the job, how much old material has to come out and access to the work. You will have a clear quote before any work starts, so you know where you stand.
Asking for a quote
What to tell us when you ask for a quote:
- Where the property is
- Photos by email, if that’s easy
- The problem you’ve noticed
- Whether it has been sealed before
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.
Nearby places to Bàgh a'Chaisteil
What else we do in Bàgh a'Chaisteil
Common questions in Bàgh a'Chaisteil
Is sand mastic in a coastal place like Bàgh a'Chaisteil any different?
Near the sea, outside joints face more wind, rain and salt than they would inland, so the choice of sealant and the preparation matter even more. Walls facing the sea are normally the first to need attention.
Do you cover smaller places like Bàgh a'Chaisteil?
Yes. Bàgh a'Chaisteil is within the area we cover, which takes in towns, villages and rural addresses. We work across all of Scotland, including the islands, where work is planned around ferry crossings. Just mention lanes, gates or anything else about the route when you book.
Can you seal over the old sealant?
No. The old sealant always comes out first, so the new joint bonds to clean surfaces.
What should I tell you?
The location, the problem and the rough size of the job. Photos by email help too.
Do I have to be there?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
How long will you be here?
Typically it takes a few hours for a single window, longer for several. Larger jobs naturally take longer, and we’ll tell you how long to expect.
Should I try DIY first?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
What does sand mastic cost?
There’s no set price, as it depends on the job: how much there is, what’s there now, how we reach it and what it needs. We agree the price before any work begins.
What sand mastic looks like in Bàgh a'Chaisteil
Bàgh a'Chaisteil 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 the mastic around older windows and doors, especially on the side facing the sea. Many older homes in Scotland have sash and case windows, often pointed into the wall with traditional sand mastic.
If you live in an older home near Church of our Lady, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Bàgh a'Chaisteil (Gaelic: Castlebay) is in Na h-Eileanan Siar. Across the HS9 area, our applicators can take on sand mastic. Our area takes in 87 places across Na h-Eileanan Siar, from the larger towns to small villages.
Here we cover the HS9 postcode area for sand mastic. Streets in the area include The Square, Rathad na Horgh and Maol Domhnaich, and we cover them all. We also cover the places around Bàgh a'Chaisteil: Castlebay (1 mile east), Ceann Tangabhal (1 mile north-west), Leideag (1 mile east), Brèibhig (2 miles east) and Cuidhir (3 miles north). Bàgh a'Chaisteil is one of the larger places we cover in Na h-Eileanan Siar. For island and remote addresses, the job takes a little more planning, so let us know when you get in touch.
What’s near Bàgh a'Chaisteil
Nearby you will also find St Brendan's Hospital (under half a mile south) and Barra Heritage & Cultural Centre (less than half a mile east). Green spaces nearby include Ben Leribreck.
When it is not the sealant
We won’t take on work that will not last, so these are the limits:
- Whether work needs listed building consent
- Decayed frames that need repair
- Crumbling stone or brickwork round the window
If you are not sure, just drop us a line at info@mrmastic.co.uk and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Brick reveals
- Period & listed homes
- Timber door frames
- Sash and case windows
- Stone surrounds
- Tenement windows
When to call us in Bàgh a'Chaisteil
Shallow joints are a common cause. Mastic that’s too thin cracks and drops out so we make sure the new mastic is the right thickness.
If you can see any of these, it’s time to have the joints looked at:
- Draughts and rain around sash boxes
- Patchy fillers round a sash window
- Modern sealant on a period surround
- Open joints round the window box
Schools such as Castlebay Community School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
Before booking anyone
- What guarantee comes with the work
- What product goes in the joint
- Whether they seal over old material or remove it
- How long to leave it before use
Why it’s worth doing now in Bàgh a'Chaisteil
New mastic over crumbling mastic won’t hold. We remove the loose material first so the new mastic stays put. When the nearest tradesperson is a drive away, it’s tempting to leave a small leak, but water behind a failed seal does the most damage when nobody’s watching.
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
Why book with us
- Neat joints and a tidy finish
- A 12-month guarantee on all work
- Full insurance on every job
- Rated 4.9 stars on Google
See our cost guide or our reviews.
How it works
Most of a good job is in the preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it usually takes a few hours per window, depending on the condition of the joints. For a place like Bàgh a'Chaisteil, longer drives are planned in advance. Mention tracks, gates, ferries or anything else about the route.
- Each surround is checked first.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
Before we arrive
- Mention any leaks or damp you’ve noticed
- Let us know about earlier repairs to the joints
- Tell us about access, such as stairs, a lift or high-level joints
Ask for a quote
To get a quote, email us at info@mrmastic.co.uk with the location and a short description of the problem. We’ll give you a clear price before any work starts.