Oxfordshire · England
External & façade joints in Blackthorn, Oxfordshire
Movement joints in Blackthorn need attention? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Sealant that has lost its bond to the brick or render
- Old sealant gone brittle and cracked
- Gaps where render, brick and frames meet
How we handle external mastic in Blackthorn
We’re ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Some surfaces need a primer before sealing. Typical jobs include gaps where render, brick and frames meet and weathered mastic that no longer stretches, on concrete & block, render & cladding joints and façade panels.
External sealant needs dry, clean surfaces, so work around Blackthorn is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
You get a one-year guarantee, the same in Blackthorn as everywhere else we work.
- Place
- Blackthorn (OX25)
- Region
- Oxfordshire
- Guarantee
- One year on every job
- Quote
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Leave it or put it right?
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. Around Blackthorn, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Why Blackthorn clients choose us
- Quality sealants from Arbo and Everbuild
- Experience in homes, commercial sites and hotels
- Every job guaranteed for a year
- White, clear, grey or another colour, product permitting
Towns and villages near Blackthorn
More services for Blackthorn
Common questions in Blackthorn
Do you cover smaller places like Blackthorn?
Yes, smaller places are covered as well as towns. We work across London and the South East. Just mention lanes, gates or anything else about the route when you book.
Do you work for landlords with property near Bicester Village station?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before work begins.
Why is there a gap in my brick wall?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It’s sealed with a flexible sealant, not mortar.
Will there be a smell?
Possibly a little. It fades as the sealant cures, and ventilation helps.
Can you seal joints between two different materials?
Yes. Materials like render, brick, metal and uPVC all move differently, so a flexible sealant is needed where they meet. We choose one that suits both surfaces.
Can a movement joint be filled with mortar?
No. Mortar locks the joint solid, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
What do you need from me for a quote?
A short description and the location. We will ask anything else we need to know.
What does external mastic cost?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote.
Keeping the joints in good condition
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Keep high-pressure jets off the joints
- Walk round the building once a year and look at the joints
- Tell anyone working on the walls about the movement joints
- Keep soil, plants and ivy away from the joints
Only paint over the joint if we’ve confirmed the sealant can take paint. Paint can crack on a flexible joint and spoil the finish.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage which cost more to put right than the joint.
The process
We bring everything the job needs with us, so you don’t need to buy or prepare anything. After a quick look at the joints together, the area is protected and the work begins. Most jobs take a few hours to a few days, depending on the length of joint and the access. In a small place like Blackthorn, access is normally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First, the joints are inspected and the access agreed.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- We apply the sealant, tool it and check the whole run.
Getting ready for the visit
- Plan for the work area to be out of bounds to pets and children
- Clear the area around the work
- Mention any leaks or damp you’ve noticed
Get a quote
For a quote, ring 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. We will give you a clear quote before any work starts.
Advice
Should I try it myself first?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
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.
Quotes for external mastic in Blackthorn
Your quote is based on your job. We take into account:
- Whether the work is at height
- The old material and how stubborn it is
- Any mould that needs treating
- Any working-time requirements on site
The cost depends on the size of the job, how hard the old material is to remove and access to the work. We give a clear quote before any work starts.
What to tell us for a quote
Photos by email are helpful but not essential. Please mention:
- The type of property
- How we’d reach the joints
- The rough size of the job
- Photos by email, if that is easy
Asking for a quote is easy: let us know the job and the location. A few photos by email make the job easier to understand, and we will take it from there.
Landlord and commercial work in Blackthorn
For anyone letting property in or around Blackthorn, several properties can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
Letting agents often deal with us directly. Tell us the address, the job and how access works and we’ll quote.
When it isn’t the sealant
We’d rather tell you now than do work that won’t last, so here’s what sealant cannot put right:
- Adding movement joints to masonry that has none
- Rising or penetrating damp from elsewhere in the wall
- Loose or hollow render, which needs re-rendering
Not sure which it is? You can ring 0345 464 0079 or email us and we’ll tell you honestly.
What we seal
- Copings & trims
- Concrete & block
- Render & cladding joints
- Brickwork movement joints
- Façade panels
- Joints between brick and frames
Walls and rooflines in Blackthorn
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. Historic houses like Boarstall Tower (about 3.3 miles south) are a reminder that the area around Blackthorn has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
Managing a site like Five Acres Primary School? Then larger buildings have long runs of movement joint that eventually need resealing. In the older streets around Church of St Mary the Virgin, older walls, gutters and the joints where extensions meet them need a flexible sealant. Rented homes near Bicester Village station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Blackthorn is about 3 miles south-east of Bicester, in Oxfordshire. Across the OX25 area, we cover external mastic for homes and businesses. Blackthorn is one of 443 towns and villages in Oxfordshire where we work for external mastic. You can also see our page for Oxford, about 10 miles away.
We cover every part of the OX25 postcode area for external mastic and the streets around it. That includes homes and businesses on Station Road, Lower Road and Thame Road and the roads around them. We also cover the places around Blackthorn: Piddington (2 miles south-east), Ludgershall (3 miles south-east), Grendon Underwood (4 miles east), Edgcott (4 miles north-east) and Brill (4 miles south-east). We also work in nearby towns such as Oxford (10 miles south-west), Bicester (3 miles north-west), Thame (10 miles south-east), Kidlington (9 miles south-west), Chinnor (14 miles south-east) and Headington Quarry (9 miles south-west).
Near you in Blackthorn
Blackthorn’s nearest station is Bicester Village station, about 2.6 miles north-west of the centre. Other landmarks nearby include Bicester Community Hospital (3.1 miles north-west) and Bicester Village (2.8 miles north-west). For a walk, there’s Upper Ray Meadows and Graven Hill.