Highland · Scotland
Thurso Window Mastic
Professional window mastic in and around Thurso, with old sealant always removed completely and a 12-month guarantee.
- Cracked sealant at the sill ends
- Rushed sealant from a window installation
- Sealant in the wrong colour for the frame
Window mastic in Thurso
Behind a thin line of old mastic there’s sometimes a deep void. Filling it with sealant alone leaves a joint that cannot move properly, so deep gaps get backing rod first. That way the new bead bonds to the frame and the wall only. If you have damp patches on the reveal after heavy rain and cracked sealant at the sill ends, we can put it right, whatever the surface.
Harled walls are common in Scottish towns like Thurso, and sealing a frame against rough harling takes a sealant that grips and moves. A thin bead that hasn’t been worked into the surface soon lets water behind it.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Place
- Thurso (KW14)
- Region
- Highland
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
Aftercare tips
Aftercare is simple, and it makes a real difference:
- Do not use solvent cleaners on the joint
- Use gentle cleaners on frames and sealant
- Do not aim a pressure washer at the joints
- Repaint timber before it’s bare
Silicone can’t generally be painted, so mention any painting plans before we start. We can use a paintable sealant where that matters.
On timber windows, water behind the joint can lead to rot. Rotten timber needs a joiner, not a sealant, so early resealing is worth it.
Thurso questions
Does the coastal weather in Thurso affect outside sealant?
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 usually the first to need attention.
Can you do window mastic in Thurso?
Yes, Thurso is within the area we cover. We work across all of Scotland. You can email us at info@mrmastic.co.uk and let us know what needs doing.
Can resealing stop a draught around my window?
Often, yes. The gap between frame and wall is a common source of draughts, and sealing the inside and outside joints closes that path.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises. Working times can be discussed when we quote.
Do you have sealant for grey or black windows?
Yes, we choose a colour to suit the frame. Anthracite grey, black, brown and white cover most frames, with clear as an option.
Do you guarantee window mastic?
Yes. Every job comes with our 12-month guarantee, and we are fully insured.
Do I need to be at home?
If the work is inside, we need someone to let us in. After that, you can carry on with your day.
What sealant do you use?
Each joint gets the product that suits it. Movement, water and weather all affect the choice.
Surface by surface
Window sills
The end joints of a sill tend to fail before the rest. We reseal them so rain cannot run into the wall.
uPVC windows
Fitters’ mastic on plastic frames is sometimes thin and rushed. We cut it out, back any deep gaps and reseal properly.
Work for landlords, hotels and businesses
We work for landlords and letting agents as well as homeowners. Resealing between tenancies is a simple way to keep a property in good order.
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we’ll quote.
What sealant work cannot fix
To be straight with you, some problems need a different trade:
- Damp problems in the wall away from the window
- A sash or casement that won’t close properly
- A failed sealed unit that has misted up
If you’re not sure, just send an email to info@mrmastic.co.uk and we will give you a straight answer before booking.
Joints and surfaces we work on
- Timber windows & doors
- Composite doors
- Window sills
- Aluminium frames
- uPVC windows
- Patio & French doors
DIY versus a professional finish
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so just mention it when you contact us.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
Window mastic in Thurso: local notes
Thurso 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. That is 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 failed outside joints work against that.
If you look after a building such as Thurso High School, its window and door frames need their mastic kept sound, just like a home’s. Rented homes near Thurso station change hands often, and cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Thurso is in Highland. We carry out window mastic for homeowners, landlords and businesses in Thurso, as part of our work across Highland. Thurso is one of 253 towns and villages in Highland where we work.
Postcode districts we cover here for window mastic: KW14. We cover properties on Sir John's Square, Gerry Square and High Street. Thurso sits on or near the A9 and A836. We also cover the places around Thurso: Scrabster (2 miles north-west), Glengolly (2 miles south-west), Janetstown (3 miles south-west), Murkle (3 miles east) and Forss (4 miles west). Thurso is among the bigger towns we cover in Highland. If you’re somewhere remote, the job takes a little more planning.
Around Thurso
There’s a railway station in Thurso itself: Thurso station. Other landmarks nearby include Scrabster Castle (0.7 miles north-west) and Thurso Heritage Museum (0.6 miles north-west).
What else we do in Thurso
What happens if it’s left?
Once mastic fails, rain can get between the frame and the wall. Over time that can mean damp patches, damaged plaster and rotting timber. Resealing now is a small job by comparison. For landlords in Thurso, damp and leaks can fall under the Repairing Standard. Sorting failed joints early is easier than dealing with a tenant’s complaint.
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs. Call for a quick quote and we’ll go through it with you.
Why Thurso customers choose us
- Trusted Arbo and Everbuild sealants
- 180+ five-star Google reviews
- You choose the colour before work begins
- Any old sealant cut out fully, not covered over
See our cost guide and customer reviews.
The process
Most of a good job is in the preparation, so that is where we spend the time. Every joint is cleaned and dried before new material goes in. In total, it normally takes a morning for a couple of windows and a door. For a job in Thurso, tell us where the work is, how to get in and where to park. Outdoor jobs need a dry day, so they can move if the weather turns.
- We check how each frame can be reached safely.
- Old, cracked mastic is removed completely.
- Frame and wall are cleaned and must be dry before sealing.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
How to prepare
- On commercial sites, let us know about site rules
- Clear the area around the work
- Let us know about stairs, lifts or work at height
Ask for a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is. Whenever you are ready, email us at info@mrmastic.co.uk.