Buckinghamshire · England
External & façade joints in California, Buckinghamshire
Specialist external mastic for California: the right sealant, proper preparation and a neat finish. Ask us for a quick quote.
- Brick movement joints where the sealant has split
- Cracked joints where brick meets render or frames
- Weathered mastic that no longer stretches
About our external mastic in California
Ground-floor and low-level joints are straightforward to reach. Where joints are higher up, tell us about the building when you get in touch and we will confirm what’s needed to reach them safely. If you have water getting into walls through failed joints and joints pointed up with cement by mistake, we can put it right.
In and around California, older properties sit alongside newer ones, each with its own outside joints. Older homes need their gutter and trim joints kept tight, newer ones their movement joints.
All our work is covered by a one-year guarantee, wherever you are in Buckinghamshire.
- Where
- California (HP21, HP20, HP19)
- Region
- Buckinghamshire
- Cover
- One year on every job
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
What external mastic looks like in California
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Managing a site like Oak Green School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Aylesbury station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
California is about 1 mile south of Aylesbury, in Buckinghamshire. We carry out external mastic for homeowners, landlords and businesses in California. Our area takes in 263 places across Buckinghamshire, from the larger towns to small villages. You can also see our page for Oxford, about 18 miles away.
All of HP21, HP20 and HP19 is covered for external mastic, from the main roads to the quietest streets. We cover properties on Lee Road, Penn Road and Eaton Road. You’ll find California on the A41 and A418, so it’s easy for us to get to. We also cover the places around California: Aylesbury (1 mile north), Walton (1 mile east), Queens Park (1 mile east), Southcourt (1 mile south) and New Zealand (1 mile north). Larger places within reach include High Wycombe (13 miles south), Chesham (11 miles south-east), Buckingham (15 miles north-west), Amersham (13 miles south-east), Princes Risborough (6 miles south) and Haddenham (6 miles south-west).
Landmarks near California
Locally, jobs take us to homes and businesses close to Pebble Brook School, Buckinghamshire UTC and King's Head Inn, among other places. There’s a railway station in California itself: Aylesbury station. Well-known places in the area include Friars Square (less than half a mile north-east) and Dinton Castle (3.4 miles west). Not far away are Beacon Hill.
Keeping the joints in good condition
A little care helps the new joints last. Our advice:
- Fix overflowing gutters above sealed joints
- Clear growth from the base of walls and joints
- Have failed joints looked at early
- Walk round the building once a year and look at the joints
Don’t let soil, plants or ivy build up against the new joints. Anything that holds water against the joint wears it out sooner.
If you can see gaps, plants or bare sections in a joint, have it checked. Early work is quicker and leaves a better finish.
When something else is needed
New sealant cannot fix everything, and we’d rather say so up front. Sealant will not put right:
- Movement that’s more than a sealant joint can take
- Walls that need new movement joints cut into them
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
If in doubt, phone 0345 464 0079 or send us an email and we’ll say what we think before booking.
Where we work in California
- Façade panels
- Brickwork movement joints
- Render & cladding joints
- Concrete & block
- Copings & trims
- Joints between brick and frames
Surface by surface
Concrete and blockwork
Concrete and block walls shrink as they dry and move with temperature. Their movement joints are sealed over backing rod with a flexible sealant.
Brickwork movement joints
Brick walls have vertical movement joints to absorb expansion. They’re resealed over backing rod with a low-modulus sealant.
Places near California
What else we do in California
DIY sealant or a professional job?
If you’ve already had a go yourself, that’s fine. We cut it out and start again, so just mention it when you contact us.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
The process
You do not need to clear the whole room or building, just the space around the work. We protect the rest, and the work takes a few hours for a handful of joints, longer for a whole elevation in most cases. For a job in California, we agree the time, the access and parking before the day. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- Mention any parking rules near the property
- Move anything stored near the joints
- Keep pets and children clear of the area while we work
Getting a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we’ll explain how we’d tackle it. Whenever you are ready, phone 0345 464 0079 or email us.
Related advice
Signs you need external mastic in California
Poor preparation causes many early failures: dusty or wet faces, no primer where one was needed, or old sealant left in. The new sealant then lets go long before it should.
People generally contact us when they notice one of these:
- Joints where the bead has come unstuck
- Rigid filler in a joint that should flex
- Weathered mastic that no longer stretches
- Joints with sealant missing in places
If you live in an older home near Church of St Mary, an extension built onto an older house moves differently, and the joint between them takes the strain.
What your quote should include
- What product goes in the joint
- What insurance they hold
- How hidden problems are handled
- The length of the guarantee
California questions
Is California within the area you cover?
Yes, we do. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Can you do external mastic in California?
Yes. Our work covers London and the South East, and California is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing, and we’ll send you a clear quote.
Can you seal joints between render and window frames?
Yes. Joints between dissimilar materials are a big part of external work. The sealant is chosen to bond to both sides, primed where needed.
I rent my home. Can I book you?
Yes. Ask your landlord first, and we can send them the quote if that helps.
How long does external mastic take?
Most jobs take a few hours to a few days, depending on the length of joint and the access, including preparation and clearing up. We’ll confirm how long when we quote.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, which is run for the Arbo sealant brand.
What does external mastic cost?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote.
Is there any odour?
Possibly a little. Any smell clears as the sealant cures, and ventilation helps.
What affects the quote in California
Every job gets its own quote. This is what makes a difference:
- Access and height
- The amount of work
- When we can work, for business premises
- Mould in or behind the old joints
The cost depends on the size of the job, how much old material has to come out and how easy the joints are to reach. We give a clear quote before we start.
Helping us quote
When you contact us, these details help:
- Pictures of the joints, sent by email
- If someone has resealed it before
- How many joints, rooms or windows are involved
- The type of property
There’s no standard price list, because every job is different. Instead, we send you a clear quote for your job. To get started, ring 0345 464 0079 or drop us an email.