Shetland Islands · Scotland
Lerwick Window Mastic
Professional window mastic in and around Lerwick, with old sealant always removed completely and a one-year guarantee.
- Gaps between the frame and the inside reveal
- Cracked sealant at the sill ends
- White mastic on grey or black frames
Different surfaces, different methods
Window sills
Every drop off the glass ends up on the sill, so the sill ends and the joint under the frame are vital. They’re cut out and resealed with exterior sealant.
Patio & French doors
Door frames take knocks and movement every time the doors are used. The sealant must cope with it.
How we handle window mastic in Lerwick
Over two decades of sealing frames has taught us which products suit which walls. We are fully insured ARBOMaster approved applicators, and every job is covered by a 12-month guarantee. Typical jobs include cold air getting in at the frame edge and cracked sealant at the sill ends, on aluminium frames, uPVC windows and window sills.
Many older Scottish homes still have timber windows set into stone walls. The sealant has to suit the stone, which rules out acetoxy silicones that can mark or attack it.
You’re covered for a year from the day we finish. If there’s a problem with it, please send an email to info@mrmastic.co.uk.
- Place
- Lerwick (ZE1)
- Wider area
- Shetland Islands
- Cover
- 12 months on all our work
- Quote
- A clear price before any work starts
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
Places near Lerwick
More services for Lerwick
The process
There isn’t much for you to do on the day. Show us the job and we’ll take it from there. The work itself takes a few hours for a few frames, or a day or more for a whole house, including the tidy-up. In smaller Scottish places, parking is generally less of an issue than access and distance. Let us know how to find you and how to reach the joints.
- Each frame is looked over and we agree which ones need resealing.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
How to prepare
- On commercial sites, let us know about site rules
- Mention if the joints have been sealed before
- Tell us about access, such as stairs, a lift or high-level joints
Get a quote
For window mastic in Lerwick, send an email to info@mrmastic.co.uk. Tell us what the problem is and where, and we will agree the price before any work begins.
Related advice
Quotes for window mastic in Lerwick
There’s no set price list, because no two jobs are the same. What we look at:
- Which sealant suits the joint
- The number and length of the joints
- The old material and how stubborn it is
- Mould in or behind the old joints
The cost reflects the work involved, not guesswork. That is why we ask a few questions first and send you a clear quote before any work starts.
Asking for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- Roughly how big the job is
- How we’d reach the joints
- What the problem is, such as mould, gaps, leaks or cracking
- Pictures of the joints, sent by email
For a quick quote, get us on the phone, or email us if that is easier. Tell us about the joints that need doing and we’ll explain what’s involved.
What window mastic looks like in Lerwick
Lerwick 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 the mastic around window and door frames, especially on the side facing the sea. Under the Repairing Standard, private landlords in Scotland have to keep homes wind and watertight, and sound outside sealant is part of that.
Schools such as Anderson High School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Lerwick is in the Shetland Islands. If you need window mastic in Lerwick, please drop us a line at info@mrmastic.co.uk for a quick quote. We’re based in Crawley and cover the Shetland Islands. Lerwick is one of 63 towns and villages in the Shetland Islands where we work for window mastic.
Postcode districts we cover here for window mastic: ZE1. Local streets include High Street, Market Street and Church Road, and we cover them all. You’ll find Lerwick on the A969 and A970, so it’s easy for us to get to. If you are just outside Lerwick, we cover Sound (1 mile south-west), Gremista (1 mile north), Heogan (1 mile north-east), Grindiscol (2 miles south-east) and Gunnista (2 miles north-east). Lerwick is one of the larger places we cover in the Shetland Islands. Remote and island addresses need a little more planning, so tell us where you are when you ask for a quote.
Landmarks near Lerwick
Locally, jobs take us to homes and businesses close to Gilbertson Park and Grand Hotel, among other places. Well-known places in the area include Gilbert Bain Hospital (within half a mile south) and Shetland Museum (less than half a mile north-east). The countryside around Lerwick includes Setter Hill and Clickimin Loch.
Landlord and commercial work in Lerwick
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Letting agents and landlords in Lerwick can book us as well as householders. Resealing between tenancies keeps a property looking cared for.
DIY versus a professional finish
The biggest DIY mistake is sealing over old sealant. New silicone will not bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Signs you need window mastic in Lerwick
Every frame moves through the day. Sun on a frame makes it expand, and it contracts again overnight, while the brick or render around it hardly moves. If the sealant can’t stretch, it splits.
The most common problems we see are:
- A bead that doesn’t match the frame
- Cracked sealant at the sill ends
- Hard, cracked sealant around windows
- Whistling draughts around closed windows
Homes close to St Margaret's Roman Catholic Church include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Comparing quotes
- What guarantee comes with the work
- How long to leave it before use
- What preparation is included
- How much experience the applicator has
How to look after the new joints
Good habits help new joints last longer. A few tips:
- Don’t aim a pressure washer at the joints
- Avoid harsh chemicals near the mastic
- Air rooms to keep condensation down around windows
- Look round the frames every year or so
Keep sill grooves and drainage slots clear, so rain drains out rather than building up at the sealant.
A failed joint lets water into the wall a little at a time. Often the first sign is a damp patch inside or flaking paint on the reveal. Catching it early keeps the fix to a reseal.
FAQs for Lerwick
Do you cover Lerwick for window mastic?
Yes, Lerwick is within the area we cover. We work across all of Scotland. You can drop us a line at info@mrmastic.co.uk and let us know what needs doing.
Will you come out to Lerwick?
Yes, Lerwick is covered. We work across all of Scotland, islands included, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
What should I tell you?
A short description and the location, with photos by email if possible. We will ask anything else we need to know.
Do I need to be at home?
That depends on where the joints are. Inside work needs someone to give us access, and for outside work we’ll agree access with you when we book.
Do you work for letting agents?
Yes. As well as householders, we work for landlords, agents, businesses and hotels across the Shetland Islands.
Is it worth trying it myself?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.
How long does it take to reseal the windows on a house?
A handful of frames is a short visit. You’ll get a timescale with the quote.
I rent my home. Can I book you?
We’re happy to deal with the tenant, landlord or agent. Just make sure your landlord agrees.