Argyll and Bute · Scotland
Dunoon External Mastic
External mastic across Dunoon and nearby, with every bit of old sealant taken out first.
- Leaking joints around cladding and façade panels
- Sealant pulling away from one side of the joint
- Old sealant gone brittle and cracked
Signs you need external mastic in Dunoon
Every building moves. Brickwork grows a little over the years, blockwork and concrete shrink, and all of it moves with heat and moisture. The sealant in the movement joints takes that strain.
It’s worth asking for a quote if you see:
- Rain getting behind render or cladding at a joint
- Hard, crazed mastic that has stopped moving
- Sealant that has lost its bond to the brick or render
- Failed sealant between panels on a façade
If you let a flat or house near Inverkip station, failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Questions to ask before booking
- Who turns up on the day
- Whether you can choose the colour
- What happens if the job turns out different
- Is the old sealant removed completely?
External mastic for homes and businesses in Dunoon
Short cuts in external joints show up within a season or two. Overfilled joints, missing backing rod and sealant laid over old sealant rarely last long. We strip the joint back and start again. If you have movement joints filled with mortar instead of sealant and brick movement joints where the sealant has split, we can put it right, on concrete & block, copings & trims and render & cladding joints alike.
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.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Location
- Dunoon (PA23)
- Wider area
- Argyll and Bute
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- info@mrmastic.co.uk
- Page updated
- 26 October 2026
Quotes for external mastic in Dunoon
We do not publish a price list, because jobs vary so much. What we look at:
- Whether there’s mould to deal with
- The number of rooms or windows
- Which sealant suits the joint
- Access and height
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Asking for a quote
You do not need to know the technical terms. Just tell us:
- What’s wrong with the joints now
- Where the job is, and your postcode
- The rough size of the job
- Any previous sealing or DIY work
There’s no standard price list. Instead, your job gets its own clear quote. To arrange one, email us at info@mrmastic.co.uk.
Why deal with it now?
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That protects surfaces like brick, render and concrete. A stiffer product can damage the joint edge as it fails. Out of town in Scotland, exposed walls take a lot of weather, and once water gets behind a failed joint, damp in stone or harled walls is slow to dry out.
Doing several joints on one visit is usually more efficient than separate visits, so it’s worth mentioning everything you’d like done. You will get one clear quote for the whole job.
Why choose Mr Mastic in Dunoon
- Tidy, careful work
- Every job guaranteed for a year
- ARBOMaster approved applicator
- Anti-fungal sanitary silicone in wet areas
Read our cost guide and our reviews.
Can I do it myself?
Some sealant jobs are within reach of a careful DIYer, 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 a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
What happens on the day
Good joint work is mostly 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 anything from a few hours to several days, depending on the building. Outside jobs in Dunoon need a dry day, because sealant won’t bond to a wet joint, so an outdoor job can move if the forecast changes. Work indoors is not affected.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Tell us if parking is tricky
- Let us know about stairs, lifts or work at height
- Try not to wet indoor joints just before the visit
Get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.
Related advice
FAQs for Dunoon
Is external mastic in a coastal place like Dunoon any different?
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.
Do you cover smaller places like Dunoon?
Yes, we do. Our work covers the whole of Scotland, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Can you quote for more than one area?
Yes, and it often makes sense. Combining jobs makes good use of the visit, so mention them when you ask for a quote.
How long does external mastic take?
As a guide, most jobs take a few hours for a handful of joints, longer for a whole elevation. Bigger jobs take longer.
Can you seal over the old sealant?
No. Fresh sealant does not stick to old sealant, and it traps any mould or water underneath. It all has to come out first.
Is there any odour?
There can be a smell while the sealant cures. Opening a window helps.
What should I tell you?
The location, the problem and the rough size of the job. Photos by email help too.
I rent my home. Can I book you?
Of course. Ask your landlord first, and we can send them the quote if that helps.
External mastic in Dunoon: local notes
Dunoon 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 movement joints and outside wall joints, which can dry out and crack sooner where a building faces the weather. Plenty of Scottish homes have harled walls, and joints where harling meets other materials need a sealant that can grip and flex.
If you live in an older home near St John’s Church (Dunoon), the joints between older walls, newer extensions and the roofline need a sealant that can move. Managing a site like Dunoon Primary School And Janitor's House? Then its movement joints, gutters and trims need looking after like any other building’s.
Dunoon (Gaelic: Dùn Obhainn) is about 6 miles west of Greenock, in Argyll and Bute. Jobs in Dunoon get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Across Argyll and Bute, we cover 118 places, and Dunoon is one of them. For nearby work, see our Glasgow page (26 miles or so).
Jobs for external mastic in PA23 works the same way as everywhere else we cover. That includes homes and businesses on Queen Street, Queens Court and Pilot Street. Dunoon sits on or near the A815 and A885. Close by, we work in Kirn (1 mile north-east), Hunters Quay (1 mile north-east), Bullwood (2 miles south), Sandbank (2 miles north) and Strone (2 miles north). Further out, we also cover Helensburgh (9 miles north-east), Rothesay (10 miles south-west), Rhu (7 miles north-east), Garelochhead (10 miles north-east), Port Bannatyne (9 miles south-west) and Innellan (5 miles south). As one of the bigger places in Argyll and Bute, Dunoon has homes, rented property and businesses of every kind. If you’re somewhere remote, a little more planning is needed, so mention it when you ask for a quote.
Landmarks near Dunoon
Around Dunoon, our work takes us to homes and buildings near Dunoon Grammar School, among other places. Dunoon’s nearest station is Inverkip station, about 3.9 miles south-east of the centre. Other landmarks nearby include Dunoon Castle (0.6 miles south) and Castle House Museum (0.6 miles south). The countryside around Dunoon includes Loch Loskin.
What else we do in Dunoon
Work for landlords, hotels and businesses
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we’ll quote.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. Our tips:
- Act on the first splits you see
- Look over the joints every year, ideally after winter
- Tell anyone working on the walls about the movement joints
- Never let anyone fill a movement joint with mortar
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established so early resealing is worth it.