Buckinghamshire · England
Chackmore External Mastic
Our applicators work in Chackmore on sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Gaps where render, brick and frames meet
- Joints with sealant missing in places
- Hard, crazed mastic that has stopped moving
How we handle external mastic in Chackmore
External mastic is a job where short cuts show quickly. New sealant over old, joints packed with mortar and beads with no backing all tend to fail early. We strip the joint back and start again. If you have plants rooting in failed movement joints and leaking joints around cladding and façade panels, we can put it right.
Outside joints can only be sealed when they’re dry, so work in Chackmore is booked around the forecast. Let us know about access to every wall, plus any garages or outbuildings.
Whatever the size of the job, it’s backed by our one-year guarantee in Chackmore and across Buckinghamshire.
- Where
- Chackmore (MK18)
- Wider area
- Buckinghamshire
- Guarantee
- A year, on every job
- Quotes
- A clear price before we start
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What happens on the day
When we get to you, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. Most jobs then take anything from a few hours to several days, depending on the building. Somewhere like Chackmore needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Tell us if parking is tricky
- Tell us about any water getting in
- Mention if the joints have been sealed before
How to get a quote
We quote each job on its own, so the first step is telling us about yours. Simply call 0345 464 0079 or drop us an email and describe the job.
Advice
Your questions about external mastic in Chackmore
Is Chackmore in your area for external mastic?
Yes, Chackmore is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or drop us an email and let us know what needs doing.
What guarantee comes with external mastic in Chackmore?
All our work, in Chackmore and everywhere else, comes with a 12-month guarantee. We are fully insured, and an ARBOMaster approved applicator.
Do you do commercial work?
Yes. We can plan bigger jobs in stages to suit the site.
Is it OK to fill a movement joint with cement?
No. A mortar-filled joint cannot move, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status, and we are fully insured.
Will the new joint stand out?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We pick the one that suits your wall best so it does not stand out.
Are you fully insured?
Yes. We’re fully insured for every job we do.
Should I try DIY first?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. If it doesn’t work out, we can redo it.
Aftercare tips
So the new joints stay in good condition:
- Don’t let climbing plants root in the sealant
- Check the sealant is paintable before painting near it
- Show decorators and builders where the movement joints are
- Fix overflowing gutters above sealed joints
Don’t paint over the new sealant unless we have said the product is paintable. Paint can crack on a flexible joint and spoil the finish.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal with no damage behind it to deal with.
Can I do it myself?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Also near Chackmore
What else we do in Chackmore
Honest limits
It helps to know what we cannot do:
- Structural movement, which needs a surveyor or engineer
- Damp that is not coming from the joint
- Render that is blown, hollow or coming away
Not sure which it is? You can call 0345 464 0079 or drop us an email and we will tell you honestly before booking.
Where we work in Chackmore
- Concrete & block
- Brickwork movement joints
- Render & cladding joints
- Joints between brick and frames
- Façade panels
- Copings & trims
How we quote for external mastic
Jobs vary more than people expect. What affects the quote:
- How much old sealant there is and how hard it is to remove
- Whether the work is at height
- How many areas need sealing
- Mould in or behind the old joints
Combining jobs into one visit usually makes better use of the time than several visits. We’ll give you a clear quote for the lot.
What to tell us for a quote
To help us quote quickly, let us know:
- The type of property
- Access, such as stairs, a lift or height
- If someone has resealed it before
- The problem you’ve noticed
To get a quote, phone 0345 464 0079 or drop us an email with the location and a short description of the problem. You’ll have a clear quote before we start.
What the job involves on each surface
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. We cut out the old sealant and reseal with a product suited to both surfaces.
Render joints
Render has movement joints and stop beads that need sealing. They’re resealed in a sealant that suits the render.
Walls and rooflines in Chackmore
The South East is one of the drier parts 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 Stowe House (about 1.2 miles north-west) nearby, there’s older building stock in the area around Chackmore 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 St James and St John CofE Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s. In the older streets around Parish Church of St Mary, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Chackmore is about 2 miles north-west of Buckingham, in Buckinghamshire. Wherever you are in the MK18 postcode area, we can carry out external mastic at your property. 263 places in Buckinghamshire are on our list, large and small. For nearby work, see our Oxford page, about 21 miles away.
Work in MK18 is quoted and booked the same way as anywhere else. Streets in the area include Main Street, New College Court and The Maltings, and we cover them all. If you are just outside Chackmore, we cover Radclive (1 mile south-west), Dadford (2 miles north-west), Water Stratford (2 miles west) and Shalstone (3 miles west). Larger places within reach include Haydon Hill (15 miles south-east), Quarrendon Estate (15 miles south-east), Winslow (7 miles south-east), Watermead (15 miles south-east), Steeple Claydon (6 miles south) and Wingrave (15 miles south-east).
Near you in Chackmore
Around Chackmore, our work takes us to homes and buildings near Buckingham School, Akeley Wood Senior School and Stowe Park and Garden and the streets around them. A little further out are The Menagerie (1.2 miles north-west) and Buckingham Community Hospital (1.2 miles south-east). For a walk, there’s Buckingham Sand Pit.
For landlords and businesses
For anyone letting property in or around Chackmore, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.