Perth and Kinross · Scotland
External Mastic in St David's
Professional external mastic in and around St David's, with every bit of old sealant taken out first and a 12-month guarantee.
- Movement joints filled with mortar instead of sealant
- Failed seals between different materials
- Rain getting behind render or cladding at a joint
Walls and rooflines in St David's
Private landlords in Scotland must meet the Repairing Standard, which includes keeping a home wind and watertight, and failed outside joints work against that. Plenty of Scottish homes have harled walls, and joints where harling meets other materials need a sealant that can grip and flex.
In and around St David's, as anywhere, good external mastic starts with a clean, dry, properly prepared joint.
St David's is about 10 miles west of Perth, in Perth and Kinross. Wherever you are in the PH7 postcode area, we cover external mastic for homes and businesses. St David's is one of 107 towns and villages in Perth and Kinross where we work. Dundee is on our list too, about 29 miles from St David's.
All of PH7 is within our area for external mastic. We also cover Madderty (1 mile north-east), Balgowan (3 miles north-east), Aberuthven (4 miles south-east), Gilmerton (4 miles north-west) and Tullibardine (4 miles south). We also work in nearby towns such as Perth (10 miles east), Crieff (5 miles west), Kinross (15 miles south-east), Letham (9 miles east), Scone (12 miles east) and Tulloch (10 miles east).
Landmarks near St David's
A little further out are Strathallan Castle (3.5 miles south-west) and St Margaret's Hospital (4.9 miles south).
How we handle external mastic in St David's
A movement joint is a deliberate break that lets a wall expand and contract. The sealant in it has to stretch and squeeze for years, and when it fails, the wall takes the strain and water finds a way in. Common call-outs are for cracked joints where brick meets render or frames and joints pointed up with cement by mistake, across concrete & block, joints between brick and frames and render & cladding joints.
Outside joints can only be sealed when they’re dry, so work in St David's depends on the weather. Let us know about access to every wall and roofline.
There’s a 12-month guarantee on every job, large or small.
- Place
- St David's (PH7)
- Wider area
- Perth and Kinross
- Cover
- 12 months on all our work
- Quote
- Quoted before any work starts
- info@mrmastic.co.uk
- Page updated
- 26 October 2026
How it works
Once we are on site, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. After that, the work takes a few hours for a handful of joints, longer for a whole elevation. For a place like St David's, longer drives are planned in advance. Tell us about tracks, gates, a ferry crossing or anything unusual about getting there.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Keep pets and children clear of the area while we work
- Move anything stored near the joints
Ask for a quote
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and email photos if that is easy.
Read more
How the job changes by surface
Render joints
Render has movement joints and stop beads that need sealing. They’re resealed in a sealant that suits the render.
Joints between dissimilar materials
Each side of the joint may need its own preparation. Both surfaces are cleaned and primed as the product requires.
How to look after the new joints
A little care helps the new joints last. Our advice:
- Keep water from gutters off the wall
- Get split or bare joints resealed while the damage is small
- Keep movement joints as flexible joints, not mortar
- Show decorators and builders where the movement joints are
Do not paint over the new sealant unless we’ve said the product is paintable. Paint can crack on a flexible joint and spoil the finish.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage.
FAQs for St David's
Is there a guarantee on external mastic in St David's?
Every job comes with our 12-month guarantee, wherever it is. We are fully insured, and an ARBOMaster approved applicator.
Is St David's within the area you cover?
Yes. St David's is within the area we cover, which takes in towns, villages and rural addresses. Our work covers the whole of Scotland. Let us know about access, parking and anything unusual about getting there when you book.
Is it worth trying it myself?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. If it doesn’t work out, we can redo it.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status and we’re fully insured too.
Will the new joint stand out?
We choose a sealant colour to suit the brick, stone or render so the joint blends in. Exterior sealants come in a good range of colours.
Why do you put foam in the joint first?
Backing rod controls the sealant depth and keeps it off the back of the joint. Then the sealant bonds to two faces and can move.
Do you work at height?
It depends on the building. We work on joints that can be reached safely. Tell us about the building and we will confirm what access is needed.
How often do external joints need resealing?
That varies with the weather the wall faces, how much it moves and the sealant used. Sealant is a maintenance item, so check the joints once a year and renew it when it starts to fail.
Why it’s worth doing now in St David's
A properly done movement joint is an even line in a colour that suits the wall. A rushed bead with no backing looks untidy and does not last so it’s worth doing right. When the nearest tradesperson is a drive away, it’s tempting to leave a small leak, but water through a failed joint keeps working away until it’s fixed.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
Why St David's clients choose us
- Anti-fungal sanitary silicone in wet areas
- Over 20 years’ experience
- Full insurance on every job
- Any old sealant cut out fully, not covered over
Take a look at how sealant jobs are priced and what customers say.
When to call us in St David's
Some movement joints have been pointed up with mortar, often by someone who didn’t know what it was for. The joint can’t move, so the wall cracks somewhere else instead.
Common reasons people contact us include:
- Sealant that has lost its bond to the brick or render
- Brick movement joints where the sealant has split
- Panel joints letting water in
- Joints pointed up with cement by mistake
For jobs in and around St David's, choosing the right material for each joint is as important as a tidy finish.
Before you book anyone
- Is the old sealant removed completely?
- How hidden problems are handled
- How long the guarantee is
- Whether the sealant suits the joint
Landlords, agents and businesses in St David's
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
For anyone letting property in or around St David's, several properties can go on one quote. Just tell us the addresses and what each one needs.
What affects the quote in St David's
Call for a quick quote. The main things that affect it are:
- How many areas need sealing
- Whether the work is at height
- The product the joint needs
- Mould in or behind the old joints
Combining jobs into one visit is normally more efficient than separate visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
Asking for a quote
You do not need to know the technical terms. Just tell us:
- Whether it has been sealed before
- Roughly how big the job is
- Where the job is, and your postcode
- Pictures of the joints, sent by email
Need a quote? Please drop us a line at info@mrmastic.co.uk and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.