Buckinghamshire · England
Naphill External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Naphill and across Buckinghamshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Water getting into walls through failed joints
- Leaking joints around cladding and façade panels
- Joints with sealant missing in places
How we handle external mastic in Naphill
Getting the depth right is half the job. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, leaving it bonded to two faces so it can move with the wall. Typical jobs include movement joints with cracked, split or missing sealant and joints pointed up with cement by mistake, across concrete & block, joints between brick and frames and render & cladding joints.
External sealant needs dry, clean surfaces, so work around Naphill is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
A 12-month guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Naphill (HP14)
- Wider area
- Buckinghamshire
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What affects the quote in Naphill
For a quick quote, just ask. The main things that affect it are:
- Any mould that needs treating
- The size of the job
- Access and height
- The product the joint needs
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
Helping us quote
Photos by email are helpful but not essential. Please mention:
- What the problem is, such as mould, gaps, leaks or cracking
- Where the property is
- If it’s domestic, commercial or a hotel
- If someone has resealed it before
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email pictures if that’s easy.
What we cannot put right
Sealant isn’t the answer to every problem, and we’d rather say so up front. It won’t solve:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Damp that isn’t coming from the joint
- Movement that’s more than a sealant joint can take
If in doubt, phone 0345 464 0079 or email us and we will say what we think.
Surfaces we seal
- Concrete & block
- Copings & trims
- Render & cladding joints
- Brickwork movement joints
- Joints between brick and frames
- Façade panels
Signs you need external mastic in Naphill
Some movement joints have been pointed up with mortar. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Most people get in touch after spotting something like this:
- Gaps where render, brick and frames meet
- Plants rooting in failed movement joints
- Sealant that has lost its bond to the brick or render
- Movement joints filled with mortar instead of sealant
Rented homes near Saunderton station change hands often, and split movement joints are easy to miss on a rental until damp shows inside.
What your quote should include
- What preparation is included
- How the colour is chosen
- What happens if they find a problem under the old sealant
- Is the old sealant removed completely?
Nearby places to Naphill
What else we do in Naphill
FAQs for Naphill
Do you work for landlords with property near Saunderton station?
Yes. We work for letting agents and landlords as well as householders, and several properties can be quoted together. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Do you cover smaller places like Naphill?
Yes, Naphill is covered. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
How much does external mastic cost in Naphill?
Size, access and the old material all affect the cost. Ask us for a quote.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator and we are fully insured too.
What is backing rod for?
The foam is closed-cell backing rod. It keeps the sealant at the right depth and bonded to the sides only.
Where are you based?
Mr Mastic is based in Crawley. We cover Naphill and the rest of Buckinghamshire, along with the rest of our area.
What colours does the sealant come in?
Exterior sealants are made in a range of colours, from greys and browns to whites and stone shades. We pick the one that suits your wall best so it does not stand out.
Work for landlords, hotels and businesses
We also work for property managers and facilities teams. Several sites can be quoted together, and we’re fully insured.
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a 12-month guarantee.
What happens on the day
On the day, there’s very little for you to do. Point us to the joints and we’ll get on with it. The job generally takes a few hours to a few days, depending on the length of joint and the access. Somewhere like Naphill 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.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Preparing for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Tell us if parking is tricky
- Clear the area around the work
Get a quote
Want a quote for external mastic? Please call 0345 464 0079 or email us and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Related advice
Should I try it myself first?
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly, so tell us about it when you ask for a quote.
Why it’s worth doing now in Naphill
A failed movement joint lets water into the wall, behind render and cladding. Dealing with it early keeps the repair to the joint, rather than the wall around it. Older cottages and farmhouses around Naphill can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why choose Mr Mastic in Naphill
- Every job guaranteed for a year
- An ARBOMaster approved applicator
- Anti-fungal sanitary silicone in wet areas
- More than 20 years in sealant work
Take a look at what affects the cost and customer reviews.
External mastic in Naphill: local notes
With historic houses such as Hughenden Manor (about 1.5 miles south-east) nearby, there’s older building stock in the area around Naphill as well as newer homes. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material. 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.
For an older house near a landmark such as Church of St Botolph, the joints between older walls, newer extensions and the roofline need a sealant that can move. Managing a site like Naphill and Walters Ash School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Naphill is about 3 miles north-west of High Wycombe, in Buckinghamshire. Homes, rented property, offices and hotels in Naphill is covered for external mastic. Every job comes with our 12-month guarantee. 263 places in Buckinghamshire are on our list. We also work in Reading, about 17 miles from Naphill.
Postcode districts we cover here for external mastic: HP14. Whether your property is on Christopher Close, Main Road and Purssells Meadow or anywhere close by, we can help. Nearby, we also carry out external mastic in Walter's Ash (1 mile north-west), Lower North Dean (1 mile north-east), Hughenden Valley (1 mile east), Upper North Dean (1 mile north) and Downley (1 mile south). We also work in nearby towns such as Aylesbury (11 miles north), High Wycombe (3 miles south-east), Chesham (8 miles north-east), Marlow (6 miles south), Amersham (8 miles east) and Beaconsfield (7 miles south-east).
Near you in Naphill
Locally, jobs take us to homes and businesses close to The Royal Grammar School, Pipers Corner School and The Wheel pub, among other places. The closest station to Naphill is Saunderton station, roughly 2.1 miles west of the centre. Well-known places in the area include Eden (2.8 miles south) and High Wycombe Castle (2.8 miles south-east). The countryside around Naphill includes Prestwood Local Nature Reserve.