Hertfordshire · England
Burn's Green External Mastic
External mastic in Burn's Green from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Moss and dirt in joints with no sealant left
- Brick movement joints where the sealant has split
- Sealant that has lost its bond to the brick or render
How we handle external mastic in Burn's Green
Movement joints let brickwork, render and cladding expand and shrink without cracking. Its sealant has to flex with the building, season after season, so once it splits or hardens, the joint stops working and water gets in. If you have joints where the bead has come unstuck and rigid filler in a joint that should flex, we can put it right.
Outside joints can only be sealed when they’re dry, so work in Burn's Green is booked around the forecast. Tell us about access to all sides of the building, including outbuildings and garages.
Every job is covered by our one-year guarantee.
- Where
- Burn's Green (SG2)
- Wider area
- Hertfordshire
- Cover
- One year on every job
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What we do, step by step
We work through the job in order: protect, prepare, seal, tidy. For most jobs that takes a few hours to a few days, depending on the length of joint and the access. Somewhere like Burn's Green needs a little journey planning: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- First we look over the joints with you, agree which to renew and talk through access.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
How to prepare
- Mention any parking rules near the property
- Tell us about any water getting in
- For indoor joints, keep the area dry beforehand if you can
Get a quote
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we’ll talk you through the work.
Read more
What affects the cost of external mastic
We quote each job individually. This is what makes a difference:
- Access and height
- Which sealant suits the joint
- When we can work, for business premises
- The number of rooms or windows
The cost depends on how much there is to do, how much old material has to come out and how easy the joints are to reach. You will have a clear quote before any work starts.
Helping us quote
You don’t need to know the technical terms. It helps if you can tell us:
- The problem you’ve noticed
- How we’d reach the joints
- If someone has resealed it before
- Where the property is
Quotes start with a quick conversation. Describe the problem, the location and the size of the job. When it suits you, call 0345 464 0079 or drop us an email.
What sealant work cannot fix
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Cracks in the bricks or render themselves, away from the joints
- Adding movement joints to masonry that has none
- Loose or hollow render, which needs re-rendering
If you’re not sure, just call 0345 464 0079 or drop us an email and we will give you a straight answer before booking.
Surfaces we seal
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Façade panels
- Copings & trims
- Brickwork movement joints
Why act early in Burn's Green
Mortar or ordinary filler might look like a quick way to close an open joint, but it locks the joint solid. The movement then cracks the brickwork or render nearby. A flexible sealant over backing rod is what the joint needs. Older cottages and farmhouses around Burn's Green can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
A few things move the cost up or down: 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.
What you get with us
- We are fully insured
- We agree the colour with you first
- Any old sealant cut out fully, not covered over
- Neat joints and a tidy finish
Take a look at our cost guide and customer reviews.
Also near Burn's Green
Also in Burn's Green
FAQs for Burn's Green
Do you work for landlords with property near Watton-At-Stone station?
Yes, landlords and agents are among the people we work for. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear quote.
Is Burn's Green in your area for external mastic?
Yes, Burn's Green is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear quote.
How long should I leave it?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used.
What’s an expansion joint in brickwork?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It’s sealed with a flexible sealant, not mortar.
What does external mastic cost?
There’s no set price, as it depends on the job: its size, the old material, access and the product needed. We agree the price before any work begins.
Should I point up the gap in my brickwork?
No. Mortar locks the joint solid, so the movement cracks the wall elsewhere. It needs a flexible sealant over backing rod.
Do you seal joints where cladding meets other materials?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. The colour is chosen to suit.
Can you reach joints on upper floors?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher ones, send details and we will confirm the access.
What external mastic looks like in Burn's Green
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. With historic houses such as Aston Bury (about 2.1 miles west) nearby, there’s older building stock in the area around Burn's Green as well as newer homes. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth.
Rented homes near Watton-At-Stone station change hands often, and split movement joints are easy to miss on a rental until damp shows inside. Homes close to Parish Church of St Peter include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain. If you look after a building such as Benington Church of England Primary School, larger buildings have long runs of movement joint that eventually need resealing.
Burn's Green is about 4 miles south-east of Stevenage, in Hertfordshire. We carry out external mastic for homes and businesses in Burn's Green and the surrounding area. 381 places in Hertfordshire are on our list, large and small. Our London page covers work nearby, about 27 miles away.
Here we cover the SG2 postcode area for external mastic. If you are just outside Burn's Green, we cover Whempstead (1 mile south-east), Dane End (2 miles south-east), Haultwick (2 miles east), Sacombe (2 miles south-east) and Sacombe Green (3 miles south-east). We also work in nearby towns such as Stevenage (4 miles north-west), St Albans (14 miles south-west), Bishop's Stortford (11 miles east), Welwyn Garden City (7 miles south-west), Harpenden (12 miles south-west) and Hitchin (9 miles north-west).
Near you in Burn's Green
We work in homes and buildings around The Bell Public House. Burn's Green’s nearest station is Watton-At-Stone station, about 2.3 miles south. Nearby you will also find Datchworth Museum (3.7 miles south-west) and Lister Hospital (5.4 miles north-west). For a walk, there’s Astonbury Wood.
Surface by 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.
Copings and trims
A failed coping joint lets water into the top of the wall. Resealing them is a small job that protects a lot.
Keeping the joints in good condition
Once the sealant has cured, a few habits help it last:
- Leave the joints unpainted unless we have said otherwise
- Look over the joints every year, ideally after winter
- Tell anyone working on the walls about the movement joints
- Clear growth from the base of walls and joints
If you have more work done on the wall, such as new render, cladding or an opening, show the contractor the movement joints. They should be kept open and resealed, not filled.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage, all bigger jobs than a reseal.
Work for landlords, hotels and businesses
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together, and we are fully insured.
Hotels need rooms back in use, so the work can be planned room by room. We have worked in hotels as well as homes and businesses.