Hertfordshire · England
External & façade joints in Letchworth, Hertfordshire
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Letchworth and across Hertfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Joints where the bead has come unstuck
- Joints with sealant missing in places
- Failed sealant between panels on a façade
External mastic in Letchworth: local notes
Letchworth was laid out as a garden city in the early twentieth century. Its houses span the original garden city homes and later estates, so outside joints of every age need looking after. Historic houses like Hinxworth Place (about 4.5 miles north) are a reminder that the area around Letchworth has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
Managing a site like Hillshott Infant School and Nursery? Then its movement joints, gutters and trims need looking after like any other building’s. Homes close to Church of St Paul include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Letchworth is about 5 miles north of Stevenage, in Hertfordshire. For external mastic in and around Letchworth, please ring 0345 464 0079 or drop us an email for a quick quote. We cover Hertfordshire from our Crawley base, Letchworth included. Our Hertfordshire coverage runs to 381 places, and Letchworth is one of them. There’s also a page for London, roughly 34 miles from Letchworth.
Every address in SG6 is within our area for external mastic. Streets in the area include Station Road, Willian Church Road and Rowland Way, all of which we cover. Letchworth sits on or near the A505 and B656. Neighbouring places we cover for external mastic include Letchworth Garden City (1 mile west), Norton (1 mile north-east), Willian (1 mile south), Walsworth (2 miles south-west) and Poets Estate (2 miles south-west). We also work in nearby towns such as Stevenage (5 miles south), Welwyn Garden City (12 miles south), Harpenden (12 miles south-west), Hitchin (3 miles south-west), Hatfield (15 miles south) and Hertford (14 miles south-east).
Near you in Letchworth
We work in homes and buildings around Norton School, The Highfield School and Three Magnets pub. Letchworth has its own railway station: Letchworth Garden City station. A little further out are Fairfield Hospital (1.9 miles north-west) and First Garden City Heritage Museum (under half a mile south). Green spaces nearby include Purwell Ninesprings.
External mastic in Letchworth, done properly
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible sealant bridges the two. Typical jobs include brick movement joints where the sealant has split and cracked joints where brick meets render or frames, across brickwork movement joints, joints between brick and frames and concrete & block.
Letchworth mixes older houses and their gutters with newer estates of brick, render and uPVC trims. Gutter joints, fascia trims and the movement joints in newer brickwork all need sealant that can flex.
There’s a 12-month guarantee on every job, whatever its size.
- Place
- Letchworth (SG6)
- Wider area
- Hertfordshire
- Cover
- A year, on every job
- Price
- A clear price before we start
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Common questions in Letchworth
Should the sealant in an older Letchworth home be renewed?
In most cases, yes, if it hasn’t been done for a while. Sealant is a maintenance item: how long it lasts depends on use, cleaning and exposure, and many homes in Letchworth may already be on their second or third set.
Can you help a landlord with a rental near Letchworth Garden City station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or drop us an email and tell us about the property, and we’ll send you a clear quote.
Do you guarantee your work?
Yes, always. There’s a 12-month guarantee on every job, large or small.
Can I do it myself?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs.
Can you work on commercial sites?
Yes, regularly. Larger jobs can be planned room by room or area by area to suit the site.
Can you seal joints between render and window frames?
Yes. Joints between dissimilar materials are a big part of external work. We use a flexible sealant suited to both surfaces, primed where needed.
When is the sealant fully cured?
It depends on the product. Before we leave, we will tell you the cure time.
What’s an expansion joint in brickwork?
Most straight vertical gaps in brickwork are movement joints. It gives the wall room to move and needs a flexible seal, not mortar.
What happens if it’s left?
Resealing a run of joints in one go is usually better than patching one at a time. They’ve weathered the same way, and access only has to be arranged once. In a family home in Letchworth, a failed seal around a bath or a frame lets water into places you cannot see, like the floor under a bath, the back of a panel or the inside of a wall. Left alone, that means rot, damp and a bigger repair.
Every job is a little different, so each one gets its own quote. The number of joints, how easy they are to reach and the sealant needed all play a part, and we’ll explain the quote if you ask.
Why choose Mr Mastic in Letchworth
- Arbo and Everbuild products
- A 12-month guarantee on all work
- More than 20 years in sealant work
- Domestic, commercial and hotel work
See what affects the cost and customer reviews.
What sealant work cannot fix
We’ll always be straight with you, so here’s what new sealant will not do:
- Adding movement joints to masonry that has none
- Rising or penetrating damp from elsewhere in the wall
- Subsidence or other structural problems
If in doubt, call 0345 464 0079 or email us and we will say what we think before you book.
Joints and surfaces we work on
- Brickwork movement joints
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
- Façade panels
- Concrete & block
The process
Every visit runs the same way: we look at the joints together, protect the area around them, carry out the job and clear up. Most jobs take a few hours for a handful of joints, longer for a whole elevation. In Letchworth, parking is rarely complicated, though it helps to know about driveways or restrictions, and mention if the work is upstairs, in a flat or high on the outside.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
How to prepare
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
- Try not to wet indoor joints just before the visit
Get a quote
For a quote, ring 0345 464 0079 or email us and tell us where the job is and what the problem looks like. We’ll send you a clear quote before any work starts.
Read more
Looking after it afterwards
Aftercare is simple:
- Deal with leaking gutters that soak the joints below
- Ask before painting over external sealant
- Walk round the building once a year and look at the joints
- Tell anyone working on the walls about the movement joints
Look over the joints once a year, ideally after winter. Splits, gaps at the edges or plants in the joint are early warning signs.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Do you need external mastic in Letchworth?
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it can’t stretch and rips as the joint opens.
Signs it’s time to call us include:
- Panel joints letting water in
- Moss and dirt in joints with no sealant left
- Joints pointed up with cement by mistake
- Brick movement joints where the sealant has split
Letting a property close to Letchworth Garden City station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
What your quote should include
- Which colour the sealant will be
- What happens if they find a problem under the old sealant
- Whether they seal over old material or remove it
- How much experience the applicator has
Landlord and commercial work in Letchworth
Housing providers, facilities teams and property managers book us too in Letchworth and across Hertfordshire. We can quote a run of properties together, and we’re fully insured.
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
How we quote for external mastic
Call for a quick quote. The main things that affect it are:
- The product the joint needs
- How many areas need sealing
- Whether there’s mould to deal with
- Working hours on commercial sites
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.
What to tell us for a quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- The rough size of the job
- If someone has resealed it before
- Any access issues, like height or stairs
- The type of property
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 add photos by email if you can.