Na h-Eileanan Siar · Scotland
External Mastic in Nis
Sealing brickwork movement joints, render, cladding and façade joints in Nis, with a 12-month guarantee on every job. Call for a quick quote.
- Rigid filler in a joint that should flex
- Brick movement joints where the sealant has split
- Leaking joints around cladding and façade panels
FAQs for Nis
Is Nis within the area you cover?
Yes, we do. Our work covers the whole of Scotland, islands included, from towns to the smallest places. Longer journeys are simply planned in advance.
Is external mastic in a coastal place like Nis any different?
Near the sea, outside joints face more wind, rain and salt than they would inland, so preparation and the right sealant matter all the more. Walls facing the sea are generally the first to need attention.
How do you reach high-level joints?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher ones, send details and we’ll confirm the access.
What is backing rod for?
That is backing rod, a closed-cell foam. It keeps the sealant at the right depth and bonded to the sides only so it can flex with the joint.
Do the sealants smell?
There can be a smell while the sealant cures. Opening a window helps.
Can you seal joints between two different materials?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. We choose one that suits both surfaces.
Should I try DIY first?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
How often do external joints need resealing?
There’s no fixed answer: joints on exposed walls or with a lot of movement age sooner. Check them each year and reseal when they split or harden. Our work comes with a 12-month guarantee.
About our external mastic in Nis
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant in a matching colour. We work on brickwork movement joints, copings & trims and façade panels, and common reasons people get in touch are water getting into walls through failed joints and movement joints filled with mortar instead of sealant.
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.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Where
- Nis (HS2)
- Region
- Na h-Eileanan Siar
- Guarantee
- One year on every job
- Price
- A clear price before we start
- info@mrmastic.co.uk
- Last updated
- 26 October 2026
Places near Nis
What else we do in Nis
Do you need external mastic in Nis?
Some movement joints have been pointed up with mortar, often by someone who didn’t know what it was for. The joint cannot move, so the wall cracks somewhere else instead.
The problems people normally mention when they call include:
- Old sealant gone brittle and cracked
- Damp patches traced to an open external joint
- Panel joints letting water in
- Rigid filler in a joint that should flex
Around Nis, as everywhere, external mastic is only as good as the preparation behind it.
Comparing quotes
- How the colour is chosen
- Which sealant they’ll use, and why
- What the quote includes, VAT included or not
- What insurance they hold
What we do, step by step
You don’t need to clear the whole room or building, only the area right around the joints. Everything nearby is protected, and the work takes anything from a few hours to several days, depending on the building for a typical job. Around Nis, distance and access matter more than parking. Let us know how to find you and how to reach the joints, and the visit is planned around that.
- First, the joints are inspected and the access agreed.
- We cut out the old mastic and rake out anything in the joint.
- The faces are brushed clean and primed where the product requires it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
How to prepare
- Tell us about any water getting in
- Tell us about any previous sealing or DIY attempts
- Move anything stored near the joints
How to get a quote
We quote each job on its own, so the first step is telling us about yours. Just send an email to info@mrmastic.co.uk with the details, and pictures are welcome.
Advice
What external mastic looks like in Nis
Nis is within about 2 miles 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. Work on the islands has to be planned around ferry crossings and the weather, so the more notice, the better.
Schools such as Lionel School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Nis (Gaelic: Ness) is in Na h-Eileanan Siar. We provide external mastic to homeowners, landlords and businesses in Nis and the surrounding area, as part of our work across Na h-Eileanan Siar. Nis is one of 87 places in Na h-Eileanan Siar we cover for external mastic.
We cover every part of the HS2 postcode area for external mastic and the streets around it. We also cover Ness (1 mile south), Lionel (1 mile north-east), Cross (1 mile west), Lìonal (1 mile north) and Sgiogarstaigh (1 mile east). If you are somewhere remote, a little more planning is needed, so let us know when you get in touch.
Near you in Nis
A little further out are Ness Heritage Centre (0.5 miles north). Green spaces nearby include Loch Langavat.
Should I try it myself first?
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
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.
How to look after the new joints
Simple care keeps the joints in good condition. We recommend:
- Wash walls gently around the sealant
- Tell anyone working on the walls about the movement joints
- Do not let climbing plants root in the sealant
- Get split or bare joints resealed while the damage is small
Follow the cure time we give you before the joint is knocked or disturbed. Most exterior sealants skin fast but take longer to cure right through.
Leave a failed movement joint and water keeps getting into the wall. Over time it can mean damp inside, stained render or frost-damaged brick, all bigger jobs than a reseal.
Landlord and commercial work in Nis
If you manage several properties in or around Nis, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and photos by email help.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
What happens if it’s left?
Mortar or ordinary filler might look like a quick way to close an open joint, but it locks the joint solid. The wall then cracks somewhere else. The correct repair is a flexible sealant with the right backing. 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.
What you pay reflects the work, not guesswork. That is why we ask about the job first and give you a clear quote before work begins.
What you get with us
- One-year guarantee on every job
- Fully insured
- Rated 4.9 stars on Google
- A choice of colours where the product allows
Read what affects the cost and customer reviews.
When it is not the sealant
Honest advice matters more to us than a booking, so here’s what new sealant will not do:
- Cracking across the wall rather than at a joint
- Rising or penetrating damp from elsewhere in the wall
- Cutting new joints into brickwork, which is building work rather than sealant work
Not sure which it is? You can drop us a line at info@mrmastic.co.uk and we’ll tell you honestly before you book.
Surfaces we seal
- Concrete & block
- Joints between brick and frames
- Render & cladding joints
- Façade panels
- Brickwork movement joints
- Copings & trims