Hertfordshire · England
Letchworth Garden City External Mastic
Sealing brickwork movement joints, render, cladding and façade joints in Letchworth Garden City, with a 12-month guarantee on every job. Ask us for a quote.
- Brick movement joints where the sealant has split
- Failed seals between different materials
- Weeds or debris growing in open joints
About our external mastic in Letchworth Garden City
External mastic is a job where short cuts show quickly. Overfilled joints, missing backing rod and sealant laid over old sealant rarely last long. We take the old material out and do it properly. If you’re dealing with joints pointed up with cement by mistake and failed sealant between panels on a façade, we can help, whatever the surface.
Plenty of homes in a town like Letchworth Garden City have been extended, and the line where an extension meets the original house is a common leak point. Sealing it properly means the right joint depth and a flexible sealant, not a quick bead.
Every job is covered by a 12-month guarantee, wherever you are in Hertfordshire.
- Place
- Letchworth Garden City (SG6, SG7)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How it works
We bring everything the job needs with us, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take anything from a few hours to several days, depending on the building. A visit in Letchworth Garden City needs access to the work and a place to park close by. If the job is outside, mention gates, side access and anything above ground floor.
- First we look over the joints with you, agree which to renew and talk through access.
- We cut out the failed sealant and rake out any dirt or growth.
- We clean both faces of the joint and prime them where the product calls for 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.
Getting ready for the visit
- Clear the area around the work
- Let us know about parking restrictions
- Tell us about access, such as stairs, a lift or high-level joints
Getting a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, call 0345 464 0079 or drop us an email.
Related advice
Places near Letchworth Garden City
Other services in Letchworth Garden City
Can I do it myself?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
A DIY attempt does not rule out a professional job. We cut it out and start again.
Landlords, agents and businesses in Letchworth Garden City
Letting agents and landlords in Letchworth Garden City can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
For anyone letting property in or around Letchworth Garden City, jobs at different addresses can be quoted together. Send us the addresses and the work at each.
Outside joints around Letchworth Garden City
Letchworth Garden City is one of England’s garden cities, planned in the early twentieth century. Homes range from the early garden city houses to later estates, so outside joints of every age need looking after. Historic houses like Hinxworth Place (about 4.6 miles north) are a reminder that the area around Letchworth Garden City has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
For site and facilities teams at buildings such as Pixmore Junior School, its movement joints, gutters and trims need looking after like any other building’s. Homes close to St Michael include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant.
Letchworth Garden City is about 5 miles north-west of Stevenage, in Hertfordshire. Letchworth Garden City gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Our area takes in 381 places across Hertfordshire. We also work in London, around 34 miles away.
Every address in SG6 and SG7 is within our area for external mastic, from the main roads to the quietest streets. Streets in the area include Pix Road, Field Lane and Ridge Road, all of which we cover. Main roads around Letchworth Garden City include the A505. We also cover Letchworth (1 mile east), Willian (1 mile south), Norton (1 mile north-east), Walsworth (2 miles south-west) and Ickleford (2 miles west). Within a short drive, we also cover Stevenage (5 miles south-east), Welwyn Garden City (13 miles south), Harpenden (12 miles south-west), Hitchin (3 miles south-west), Hatfield (15 miles south) and Hertford (14 miles south-east).
Around Letchworth Garden City
Typical jobs here are in homes near Norton School, Three Magnets pub and Church of St Paul and the streets around them. There’s a railway station in Letchworth Garden City itself: Letchworth Garden City station. Other landmarks nearby include Wymondley Castle (2.5 miles south) and Fairfield Hospital (1.8 miles north-west). For a walk, there’s Purwell Ninesprings.
Letchworth Garden City questions
Can you help a landlord with a rental near Letchworth Garden City station?
Yes. We work for letting agents and landlords as well as householders, and several properties can go on one quote. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear price.
Can you do external mastic in Letchworth Garden City?
Yes. Our work covers London and the South East, and Letchworth Garden City is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing.
Is it messy?
Not at all. The area is protected while we work and cleaned up afterwards.
Should I point up the gap in my brickwork?
No, not where the gap is a movement joint. Filling it with mortar defeats its purpose. We will reseal it with a flexible sealant.
Are you ARBOMaster approved?
Yes. Mr Mastic is an ARBOMaster approved applicator and we’re fully insured too.
Do you take out the old sealant first?
Always. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
Can you match the colour of my brickwork?
The aim is a neat, even joint in a colour that suits the wall. We’ll talk through colour options before we start.
How often do external joints need resealing?
That varies with the weather the wall faces, how much it moves and the sealant used. Sealant is a maintenance item, so check the joints once a year.
Different surfaces, different methods
Brickwork movement joints
Clay brickwork grows slightly over its life and moves with the weather. The movement joint takes that up, so its sealant has to stay flexible.
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and helps it last.
Why it’s worth doing now in Letchworth Garden City
A properly done movement joint is an even line in a colour that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner. In Letchworth Garden City, as anywhere, most leaks start as a small gap in a joint, and early is when they’re cheapest and quickest to sort.
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you are unsure, phone 0345 464 0079 or email us for an honest opinion and a quote.
Why book with us
- 180+ five-star Google reviews
- A choice of colours where the product allows
- Full insurance on every job
- Anti-fungal silicone where joints get wet
Read what affects the cost or what customers say.
Common problems we fix in Letchworth Garden City
Sunlight, wet weather and frost wear exterior sealant down. In time it goes hard, crazes on the surface and stops stretching, so the joint eventually tears or comes away from one side.
It’s worth asking for a quote if you see:
- Cracked joints where brick meets render or frames
- Failed sealant between panels on a façade
- Rain getting behind render or cladding at a joint
- Moss and dirt in joints with no sealant left
Letting a property close to Letchworth Garden City station? Then outside joints that have cracked can let damp into a rental, so check them between lets.
Comparing quotes
- What happens if they find a problem under the old sealant
- How long to leave it before use
- What preparation is included
- What guarantee comes with the work
What sealant work cannot fix
New sealant cannot fix everything, and we’ll tell you before we start. Sealant won’t put right:
- Loose or hollow render, which needs re-rendering
- Cracks in the bricks or render themselves, away from the joints
- Cutting new joints into brickwork, which is building work rather than sealant work
If in doubt, phone 0345 464 0079 or email us and we’ll say what we think before you book.
Joints and surfaces we work on
- Façade panels
- Concrete & block
- Render & cladding joints
- Joints between brick and frames
- Copings & trims
- Brickwork movement joints