Oxfordshire · England
Charlton-on-Otmoor External Mastic
External mastic in Charlton-on-Otmoor from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Joints where the bead has come unstuck
- Old sealant gone brittle and cracked
- Joints pointed up with cement by mistake
External mastic in Charlton-on-Otmoor, done properly
Joints in render and cladding are easy to overlook until a damp patch appears. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant. If you have gaps where render, brick and frames meet and panel joints letting water in, we can put it right, on brickwork movement joints, copings & trims and render & cladding joints alike.
Somewhere as small as Charlton-on-Otmoor, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Gutter joints and wall joints there need a sealant that can flex and stay put.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Place
- Charlton-on-Otmoor (OX5)
- Region
- Oxfordshire
- Guarantee
- 12 months on all our work
- Quote
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Surface by surface
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. A flexible sealant bridges the two so neither cracks the other.
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. We reseal them with a low-modulus sealant over backing rod coloured to suit the wall.
Do you need external mastic in Charlton-on-Otmoor?
A lot of failed joints come down to preparation: joint faces that were dusty or damp, unprimed where they needed it, or still carrying old sealant. The sealant never bonds properly.
People generally contact us when they notice something like this:
- Sealant pulling away from one side of the joint
- Gaps where render, brick and frames meet
- Weeds or debris growing in open joints
- Hard, crazed mastic that has stopped moving
If you live in an older home near Church of St Mary the Virgin, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Questions to ask before booking
- What guarantee comes with the work
- Whether they seal over old material or remove it
- What insurance they hold
- What happens if the job turns out different
When something else is needed
New sealant can’t fix everything, and we will tell you before we start. Sealant won’t put right:
- Render that is blown, hollow or coming away
- Cracked brickwork or render that needs a builder or plasterer
- Walls that need new movement joints cut into them
If you are not sure, just phone 0345 464 0079 or send us an email and we’ll give you a straight answer.
Surfaces we seal
- Render & cladding joints
- Copings & trims
- Brickwork movement joints
- Concrete & block
- Façade panels
- Joints between brick and frames
Towns and villages near Charlton-on-Otmoor
Also in Charlton-on-Otmoor
Aftercare tips
Simple care keeps the joints in good condition. Our advice:
- Act on the first splits you see
- Check external joints each spring
- Keep water from gutters off the wall
- Clear growth from the base of walls and joints
Don’t paint over the new sealant unless we’ve said the product is paintable. Many exterior sealants are not designed to be painted, and paint can crack as the joint moves.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage.
Why act early in Charlton-on-Otmoor
It often makes sense to reseal all the failing joints on an elevation together. Joints of the same age tend to fail together, and access only has to be arranged once. Where a wall is exposed, as many are in small places like Charlton-on-Otmoor, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
The cost depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. We give a clear quote before we start, so you know where you stand.
Why us?
- Colour picked to suit the job
- Approved under the ARBOMaster scheme
- Fully insured
- Sanitary silicone with an anti-fungal additive in wet areas
Read what affects the cost and customer reviews.
Charlton-on-Otmoor buildings and the weather
Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Boarstall Tower (about 4 miles east) nearby, there’s older building stock in the area around Charlton-on-Otmoor as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
Schools such as Charlton-on-Otmoor Church of England Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s. If you let a flat or house near Islip station, split movement joints are easy to miss on a rental until damp shows inside.
Charlton-on-Otmoor is about 5 miles south of Bicester, in Oxfordshire. Every kind of property in Charlton-on-Otmoor can book us for external mastic. Every job comes with our one-year guarantee. We cover 443 towns and villages across Oxfordshire, large and small. You can also see our page for Oxford, roughly 6 miles from Charlton-on-Otmoor.
Here we cover the OX5 postcode area for external mastic. External mastic is available to properties on High Street, Blacksmiths Lane and Church Lane and the roads around them. If you are just outside Charlton-on-Otmoor, we cover Fencott (1 mile east), Murcott (1 mile east), Merton (1 mile north-east), Wendlebury (2 miles north) and Horton-cum-Studley (3 miles south-east). Further out, we also cover Oxford (6 miles south), Bicester (5 miles north), Abingdon-on-Thames (12 miles south), Witney (13 miles west), Thame (11 miles south-east) and Kidlington (4 miles west).
Landmarks near Charlton-on-Otmoor
Locally, jobs take us to homes and businesses close to The Crown pub, among other places. The nearest railway station is Islip station, roughly 2.3 miles west. Nearby you will also find Bicester Community Hospital (4.2 miles north) and Bicester Avenue (3.6 miles north). Not far away are Graven Hill and Otmoor RSPB reserve.
Your questions about external mastic in Charlton-on-Otmoor
Can you do external mastic in Charlton-on-Otmoor?
Yes, Charlton-on-Otmoor is within the area we cover. We work across London and the South East. Just call 0345 464 0079 or drop us an email with a few details of the job.
Do you cover smaller places like Charlton-on-Otmoor?
Yes, Charlton-on-Otmoor is covered. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
How long does external mastic last?
It varies from wall to wall: sunny, exposed elevations and busy joints wear faster. Check them each year and reseal when they split or harden. Our work comes with a one-year guarantee.
How long does external mastic take?
As a guide, most jobs take a few hours to a few days, depending on the length of joint and the access. Larger jobs naturally take longer, and we will tell you how long to expect.
Can you work on commercial sites?
Yes. Larger jobs can be planned room by room or area by area to suit the site.
Can new sealant go over the old?
No, and we never do. It can look neat for a few weeks, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.
Can landlords and businesses book you?
Yes. Domestic, commercial and hotel work are all part of what we do.
Where are you based?
We’re a Crawley-based firm. Our area covers South East England, London and Scotland.
Should I try it myself first?
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and getting the depth right matters as much as the look.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
What we do, step by step
We work through the job in order: protect, prepare, seal, tidy. Typically it takes anything from a few hours to several days, depending on the building. In a small place like Charlton-on-Otmoor, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- 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.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Keep children and pets away from the work area
- Mention any sign-in or site rules at work premises
- Mention any leaks or damp you’ve noticed
Getting a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will explain how we’d tackle it. Whenever you’re ready, call 0345 464 0079 or drop us an email.