Buckinghamshire · England
Marlow External Mastic
Movement joints in Marlow need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Hard, crazed mastic that has stopped moving
- Movement joints filled with mortar instead of sealant
- Plants rooting in failed movement joints
Surface by surface
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. We seal the joint with a flexible exterior sealant so neither cracks the other.
Brickwork movement joints
Clay brickwork grows slightly over its life and moves with the weather. That movement goes into the joint, so its sealant has to stay flexible.
How we handle external mastic in Marlow
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, so once it splits or hardens, the joint stops working and water gets in. Typical jobs include plants rooting in failed movement joints and brick movement joints where the sealant has split, across joints between brick and frames, copings & trims and façade panels.
Extensions are a common sight on houses around Marlow, and the joint where new wall meets old is a classic place for water to get in. Sealing it properly means the right joint depth and a flexible sealant, not a quick bead.
Our work is backed for twelve months, in Marlow and everywhere else we cover.
- Place
- Marlow (SL7)
- Wider area
- Buckinghamshire
- Cover
- One year on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Work for landlords, hotels and businesses
If you manage several properties in or around Marlow, jobs at different addresses can be quoted together. Send us the addresses and the work at each.
Housing providers, facilities teams and property managers book us too in Marlow and across Buckinghamshire. Several sites can be quoted together, and we are fully insured.
Signs you need external mastic in Marlow
Using the wrong sealant is another common reason. A high-modulus or general-purpose sealant can be too rigid for a busy joint, and it tears off the sides.
Signs it’s time to call us include:
- Damp patches traced to an open external joint
- Panel joints letting water in
- Movement joints filled with mortar instead of sealant
- Failed seals between different materials
If you look after a building such as Holy Trinity Church of England (Aided) School, larger buildings have long runs of movement joint that eventually need resealing.
What your quote should include
- Whether they’re fully insured
- Whether they seal over old material or remove it
- What happens if they find a problem under the old sealant
- What the cure time is
How we quote for external mastic
Every job gets its own quote. These are the things that affect it:
- Whether there’s mould to deal with
- How many rooms, windows or areas are involved
- The type of sealant required
- How easy the joints are to reach
Combining jobs into one visit normally makes better use of the time than several visits. You will get one clear quote for the whole job.
What we need to know
To make quoting easier, please include:
- How many joints, rooms or windows are involved
- The address or postcode of the job
- How we’d reach the joints
- What the problem is, such as mould, gaps, leaks or cracking
To get a quote, ring 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You will have a clear quote before we start.
Towns and villages near Marlow
More services for Marlow
Marlow: your questions answered
Is there a guarantee on external mastic in Marlow?
Every job comes with our one-year guarantee, wherever it is. We are also fully insured and ARBOMaster approved.
Can you help a landlord with a rental near Marlow station?
Yes, we work for landlords and agents. You can ring 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before we start.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises. We can talk about working times when we quote.
Where are you based?
Our base is in Crawley, and we cover South East England, London and all of Scotland.
Should I try DIY first?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used before we leave.
Why do you put foam in the joint first?
The foam is closed-cell backing rod. It stops the sealant going in too deep and bonding to three sides, which would stop it stretching.
How long does the job take?
Typically it takes a few hours for a handful of joints, longer for a whole elevation. Bigger jobs take longer, and we will tell you how long to expect.
Walls and rooflines in Marlow
With historic houses such as Harleyford Manor (about 2 miles south-west) nearby, there’s older building stock in the area around Marlow as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
If you live in an older home near Congregational Church, the joints between older walls, newer extensions and the roofline need a sealant that can move. If you let a flat or house near Marlow station, split movement joints are easy to miss on a rental until damp shows inside.
Marlow is about 4 miles south of High Wycombe, in Buckinghamshire. From the centre of Marlow to the outskirts, we cover external mastic for every kind of property, from flats and houses to offices and hotels. Our Buckinghamshire coverage runs to 263 places, and Marlow is one of them. Our Reading page covers work nearby (12 miles or so).
All of SL7 is covered for external mastic, from the main roads to the quietest streets. Whether your property is on Station Road, High Street and Willowmead Square or a nearby road, we can help. Marlow sits on or near the A404 and B482, which makes travel easy. Neighbouring places we cover for external mastic include Bisham (1 mile south), Marlow Bottom (1 mile north), Burroughs Grove (1 mile north), Temple (2 miles south) and Little Marlow (2 miles north-east). Larger places within reach include High Wycombe (4 miles north), Chesham (12 miles north-east), Amersham (10 miles north-east), Beaconsfield (6 miles north-east), Chalfont St Peter (10 miles east) and Princes Risborough (11 miles north). Marlow is one of the larger places we cover in Buckinghamshire.
Local landmarks in Marlow
We work in homes and buildings around Butcher's Tap and Sir William Borlase's Grammar School. There’s a railway station in Marlow itself: Marlow station. Other landmarks nearby include Eden (4 miles north) and High Wycombe Castle (4.1 miles north). Not far away are Carpenter's Wood.
How the visit works
When we arrive, we look over the joints with you first. We protect the surfaces around the joints before work begins. The work generally takes a few hours for a handful of joints, longer for a whole elevation. A visit in Marlow needs access to the work and a place to park close by. If the job is outside, mention gates, side access and anything above ground floor.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- Clear the area around the work
- Keep children and pets away from the work area
- For indoor joints, keep the area dry beforehand if you can
Ask for a quote
Asking for a quote is easy: tell us what needs doing and where. Photos by email help us understand the job, and we will come back to you with a quote.
Read more
What sealant work can’t fix
We’d rather tell you now than do work that will not last, so here’s what sealant cannot put right:
- Damp that is not coming from the joint
- Render that’s blown, hollow or coming away
- Subsidence or other structural problems
If in doubt, phone 0345 464 0079 or drop us an email and we will say what we think.
Joints and surfaces we work on
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
- Façade panels
- Render & cladding joints
What happens if it’s left?
Done well, a resealed joint is a neat, straight line that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner. In Marlow, as anywhere, most leaks start as a small gap in a joint, and early is when they’re cheapest and quickest to sort.
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 the work is at height. Your quote takes all of that into account.
Why book with us
- White, clear, grey or coloured to suit, where the product allows
- Old sealant always removed completely
- 20+ years of sealant experience
- Domestic, commercial and hotel work
Read how sealant jobs are priced and our reviews.