Oxfordshire · England
External Mastic in Yarnton
External mastic across Yarnton and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Weeds or debris growing in open joints
- Movement joints filled with mortar instead of sealant
- Leaking joints around cladding and façade panels
About our external mastic in Yarnton
As ARBOMaster approved applicators, we choose exterior sealants to suit the joint and the surfaces. Porous or awkward surfaces are primed where the sealant needs it. If you have old sealant gone brittle and cracked and failed sealant between panels on a façade, we can put it right, whatever the surface.
External sealant needs dry, clean surfaces, so work around Yarnton is planned for dry weather. Tell us about access to all sides of the building, including outbuildings and garages.
Big or small, you get the same one-year guarantee in Yarnton and across Oxfordshire.
- Where
- Yarnton (OX5)
- Region
- Oxfordshire
- Guarantee
- 12 months on all our work
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Landlords, agents and businesses in Yarnton
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Landlords and agents in Yarnton can book us as well as homeowners. Resealing between tenancies is a simple way to keep a property in good order before the next move-in.
What affects the cost of external mastic
The price is agreed before any work begins. It takes into account:
- The number and length of the joints
- Access and height
- Any working-time requirements on site
- Whether old sealant or filler has to be cut out
Leaving a failed joint usually makes the job bigger, not smaller. If you are not sure whether it needs doing, phone 0345 464 0079 or email us and we will give you an honest view and a quote.
Helping us quote
To make quoting easier, please include:
- The rough size of the job
- Where the job is, and your postcode
- The type of property
- Photos by email, if that’s easy
Need a quote? Please ring 0345 464 0079 or email us and tell us about the job. We’ll explain what we’d do and send you a clear quote before we start.
Common questions in Yarnton
Do you cover smaller places like Yarnton?
Yes, Yarnton is covered. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Do you work for landlords with property near Oxford Parkway station?
Yes, we work for letting agents and landlords. You can phone 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before we start.
Can you seal joints between render and window frames?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. We pick a colour that works with both materials.
Is it messy?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
Where are you based?
Our base is Crawley. We work across South East England, London and Scotland.
Do you work at height?
That depends on the building and the joints. Where joints can be reached safely, we’ll do them. Give us some details and we will confirm the access.
What sealant do you use?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
How long will you be here?
It depends on the size of the job, but as a guide it takes a few hours for a handful of joints, longer for a whole elevation. We’ll give you a better idea when we quote.
Signs you need external mastic in Yarnton
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and rips as the joint opens.
It’s worth asking for a quote if you see:
- Joints pointed up with cement by mistake
- Failed sealant between panels on a façade
- Hard, crazed mastic that has stopped moving
- Sealant pulling away from one side of the joint
If you let a flat or house near Oxford Parkway station, outside joints that have cracked can let damp into a rental, so check them between lets.
Before booking anyone
- Whether all the old sealant comes out first
- When the joint can take water or movement
- The length of the guarantee
- Whether they’re fully insured
Why it’s worth doing now in Yarnton
Sealing over the top of old mastic does not hold for long. New sealant doesn’t bond well to old, weathered sealant, so the old joint is cut out fully first. In a small place like Yarnton, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What you get with us
- Sanitary silicone with an anti-fungal additive in wet areas
- 180+ five-star Google reviews
- We are fully insured
- A 12-month guarantee on all work
See what affects the cost and our reviews.
The process
There is not much for you to do on the day. Show us the job and we’ll take it from there. The job generally takes a few hours to a few days, depending on the length of joint and the access, including the tidy-up. Somewhere like Yarnton needs a little journey planning: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We look at every joint and agree a colour to suit the wall.
- 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.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Keep pets and children clear of the area while we work
- Mention any sign-in or site rules at work premises
- Try not to wet indoor joints just before the visit
Getting a quote
For a quote, call 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. You will have a clear quote before we start.
Read more
Surface by surface
Brickwork movement joints
Vertical joints in long brick walls let the brickwork expand without cracking. They’re resealed over backing rod with a low-modulus sealant.
Concrete and blockwork
Blockwork and concrete shrink over time and move with the seasons. We reseal their joints with backing rod and a flexible product.
External mastic in Yarnton: local notes
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Blenheim Palace (about 3.2 miles north-west) are a reminder that the area around Yarnton has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
If you live in an older home near Church of St Bartholomew, an extension built onto an older house moves differently, and the joint between them takes the strain. For site and facilities teams at buildings such as William Fletcher Primary School, its movement joints, gutters and trims need looking after like any other building’s.
Yarnton is about 5 miles north-west of Oxford, in Oxfordshire. From the centre of Yarnton to the outskirts, we cover external mastic for every kind of property, from flats and houses to offices and hotels. Across Oxfordshire, we cover 443 places, Yarnton among them.
Here we cover the OX5 postcode area for external mastic. That includes homes and businesses on Dashwood Avenue, Spencer Avenue and Merton Way and the roads around them. Other places close to Yarnton include Begbroke (1 mile north-west), Worton (1 mile west), Thrupp (2 miles north), Bladon (2 miles north-west) and Shipton-on-Cherwell (3 miles north). Larger places within reach include Oxford (5 miles south-east), Didcot (14 miles south), Bicester (9 miles north-east), Abingdon-on-Thames (9 miles south), Witney (8 miles west) and Carterton (12 miles west).
Around Yarnton
In Yarnton, that means homes and buildings near The Red Lion pub and Gosford Hill School and the streets around them. For rail, the closest station is Oxford Parkway station, about 1.4 miles east of the centre. A little further out are Acland Hospital (3.8 miles south-east) and Oxford Castle (4.3 miles south-east). The countryside around Yarnton includes Harcourt Hill and Hook Meadow and The Trap Grounds.
Aftercare tips
No joint lasts for ever, but care makes a real difference. Our tips:
- Ask before painting over external sealant
- Never let anyone fill a movement joint with mortar
- Wash walls gently around the sealant
- Point out the joints to other trades
Follow the cure time we give you before the joint is knocked or disturbed. The surface skins over quickly, but full cure takes longer.
Small splits are the time to act. At that stage it’s a simple cut out and reseal with no damage behind it to deal with.