Buckinghamshire · England
External Mastic in Chalfont St Giles
Sealing brickwork movement joints, render, cladding and façade joints for householders, landlords and businesses in Chalfont St Giles. Fully insured, ARBOMaster approved and guaranteed for a year.
- Moss and dirt in joints with no sealant left
- Cracked joints where brick meets render or frames
- Joints where the bead has come unstuck
External mastic in Chalfont St Giles, done properly
Movement joints let brickwork, render and cladding expand and shrink without cracking. The sealant in it has to stretch and squeeze for years, so once it splits or hardens, the joint stops working and water gets in. We are often asked to deal with failed seals between different materials and sealant pulling away from one side of the joint, on copings & trims, joints between brick and frames and concrete & block.
Houses in smaller places like Chalfont St Giles can stand more in the open than those in a built-up town, and walls and rooflines facing the weather take the worst of it. That is where gutter joints and wall joints tend to fail first.
Each job carries a 12-month guarantee.
- Where
- Chalfont St Giles (HP8, HP9)
- Wider area
- Buckinghamshire
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
FAQs for Chalfont St Giles
I let a flat near Seer Green & Jordans station. Can you help?
Yes. We work for landlords and agents as well as householders, and several properties can be quoted together. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll send you a clear quote.
Can you do external mastic in Chalfont St Giles?
Yes, Chalfont St Giles is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or email us and let us know what needs doing, and we’ll send you a clear quote.
Should I try DIY first?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
Will the old sealant be removed?
Yes. We cut out all the old sealant and clean the joint before applying anything new.
Where do you work from?
We work from Crawley. We cover Chalfont St Giles and the rest of Buckinghamshire.
What is backing rod for?
Closed-cell backing rod sets the depth of the sealant and stops it sticking to the back of the joint. Then the sealant bonds to two faces and can move.
Do you seal joints where cladding meets other materials?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. We pick a colour that works with both materials.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that normally means someone at home.
Landlord and commercial work in Chalfont St Giles
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements.
Towns and villages near Chalfont St Giles
What else we do in Chalfont St Giles
Looking after it afterwards
Aftercare is simple:
- Never let anyone fill a movement joint with mortar
- Check the sealant is paintable before painting near it
- Fix overflowing gutters above sealed joints
- Look over the joints every year, ideally after winter
Look over the joints once a year, ideally after winter. Watch for splits, edges coming away or growth in the joint.
A joint that has stopped moving pushes the movement elsewhere, normally as cracking in the brickwork or render nearby. Resealing it early helps prevent that.
What affects the cost of external mastic
Jobs vary more than people expect. The main factors:
- The old material and how stubborn it is
- The product the joint needs
- The number and length of the joints
- Whether the work is at height
Leaving a failed joint usually makes the job bigger, not smaller. If you are unsure, phone 0345 464 0079 or send us an email and we’ll give you an honest view and a quote.
Helping us quote
Photos by email are helpful but not essential. Please mention:
- What’s wrong with the joints now
- How we’d reach the joints
- A few pictures by email, if you can
- The rough size of the job
For external mastic in Chalfont St Giles, phone 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and we’ll agree the price before any work begins.
Can I do it myself?
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is.
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Honest limits
Before booking, it’s worth knowing the limits too:
- Walls that need new movement joints cut into them
- Structural movement, which needs a surveyor or engineer
- Render that’s blown, hollow or coming away
If you are not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer before booking.
Joints and surfaces we work on
- Concrete & block
- Façade panels
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
Walls and rooflines in Chalfont St Giles
With historic houses such as Chenies Manor House (about 3.5 miles north-east) nearby, there’s older building stock in the area around Chalfont St Giles as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For landlords with property near Seer Green & Jordans station, split movement joints are easy to miss on a rental until damp shows inside. For an older house near a landmark such as Parish Church of St Giles, an extension built onto an older house moves differently, and the joint between them takes the strain. Schools such as Chalfont St Giles Infant School and Nursery are buildings too, and larger buildings have long runs of movement joint that eventually need resealing.
Chalfont St Giles is about 3 miles south of Amersham, in Buckinghamshire. Jobs in Chalfont St Giles get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Chalfont St Giles is one of 263 towns and villages in Buckinghamshire we cover for external mastic. Our Reading page covers work nearby.
Our applicators cover all of the HP8 and HP9 postcode area for external mastic. External mastic is available to properties on High Street, London Road and Milton Hill and the roads around them. Close by, we work in Chalfont Common (1 mile south-east), Jordans (2 miles south-west), Chalfont St Peter (2 miles south-east), Horn Hill (2 miles east) and Heronsgate (2 miles east). We also work in nearby towns such as High Wycombe (8 miles west), Chesham (6 miles north), Marlow (9 miles south-west), Amersham (3 miles north), Beaconsfield (4 miles south-west) and Princes Risborough (13 miles north-west).
What’s near Chalfont St Giles
Locally, jobs take us to homes and businesses close to Miltons Head pub, British Defence Film Library and The Chalfonts Community College and the streets around them. Chalfont St Giles’s nearest station is Seer Green & Jordans station, about 2.1 miles south-west. A little further out are Chalfonts and Gerrards Cross Hospital (1.7 miles south) and Chiltern Open Air Museum (1.4 miles east). Green spaces nearby include Long Grove Wood and Pynesfield Lake.
Why deal with it now?
The longer a joint stays open, the more water the wall takes in. In cold weather, frost can damage wet brick and render around the joint, so the problem grows beyond the joint itself. In a smaller place like Chalfont St Giles, wherever a wall is exposed, a failed outside joint is a real source of damp. Inside, a split seal lets water into floors and panels just as it would anywhere.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
Why book with us
- Trusted Arbo and Everbuild sealants
- Experience in homes, commercial sites and hotels
- Over 20 years’ experience
- Sealant colour chosen to suit
Take a look at our cost guide or our reviews.
What happens on the day
There’s no need to move everything out before we come, only the area right around the joints. We protect the rest, and the job takes anything from a few hours to several days, depending on the building for a typical job. A visit to Chalfont St Giles is planned like any other: the time, the access and where to park are agreed in advance. 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.
- The faces are brushed clean and primed where the product requires 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
- Let us know about stairs, lifts or work at height
- Keep children and pets away from the work area
- Let us know if you’ve seen damp or leaks
Get a quote
Want a quote for external mastic? Please phone 0345 464 0079 or drop us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.