Hertfordshire · England
External Mastic in Hitchin
External mastic for Hitchin, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Rain getting behind render or cladding at a joint
- Sealant that has lost its bond to the brick or render
- Joints pointed up with cement by mistake
External mastic in Hitchin, 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. If you are dealing with cracked joints where brick meets render or frames and moss and dirt in joints with no sealant left, we can put it right, whatever the surface.
Hitchin mixes older houses and their gutters with newer estates of brick, render and uPVC trims. All of those joints move, so they need a flexible sealant rather than a rigid filler.
We guarantee the work for a year. If something is not right with it in that time, tell us and we will put it right.
- Location
- Hitchin (SG4, SG5)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
The process
On the day, there’s very little for you to do. Point us to the joints and we’ll get on with it. The work itself takes a few hours to a few days, depending on the length of joint and the access. For a job in Hitchin, we need access to where the work is and somewhere nearby to park. For outside work, let us know about side access, gates and any upper-floor joints.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Preparing for the visit
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
- Clear the area around the work
Get a quote
For external mastic in Hitchin, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before we start.
Related advice
Landlords, agents and businesses in Hitchin
Letting agents often deal with us directly. Tell us the address, the job and how access works.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Why deal with it now?
Sealing over the top of old mastic doesn’t hold for long. The new layer can’t bond properly to old, weathered material, so we always take the old sealant out. In a family home in Hitchin, 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. Whatever the joint, failed sealant only gets worse.
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or send us an email.
Why book with us
- We are fully insured
- Sealant colour chosen to suit
- We agree the colour with you first
- An ARBOMaster approved applicator
Read how sealant jobs are priced or our reviews.
More services for Hitchin
Hitchin questions
I let a flat near Hitchin station. Can you help?
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.
Can you do external mastic in Hitchin?
Yes, Hitchin is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or send us an email and let us know what needs doing, and we’ll give you a clear price.
Are you insured?
Yes, we are fully insured.
Can I do it myself?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. If it doesn’t work out, we can redo it.
When will the joints need doing again?
It varies with how exposed the wall is and how much the joint moves. Look for splits, hardening or edges coming away.
What colours does the sealant come in?
The sealant colour is picked to suit the wall. Exterior sealants come in a good range of colours.
What’s an expansion joint in brickwork?
Walls move with heat, cold and moisture, so long walls have planned gaps to take that movement. The gap is sealed with a flexible sealant over backing rod.
Are you ARBOMaster approved?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
When to call us in Hitchin
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it cannot stretch and rips as the joint opens.
These are the problems we’re asked about most:
- Joints pointed up with cement by mistake
- Failed sealant between panels on a façade
- Old sealant gone brittle and cracked
- Gaps where render, brick and frames meet
Homes close to Church of the Holy Saviour include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Questions to ask before booking
- Which colour the sealant will be
- Whether all the old sealant comes out first
- Whether VAT is included
- How hidden problems are handled
How we quote for external mastic
The quote reflects the job in front of us. We look at:
- How many areas need sealing
- Access and height
- The product the joint needs
- The number and length of the joints
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we will go through it with you.
Asking for a quote
What to tell us when you ask for a quote:
- Whether it’s a home or a business
- How we’d reach the joints
- What the problem is, such as mould, gaps, leaks or cracking
- If someone has resealed it before
Want a quote for external mastic? Please phone 0345 464 0079 or email us with a few details. You’ll know what we plan to do, and what it will cost, before any work begins.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Make sure movement joints are not pointed over
- Keep soil, plants and ivy away from the joints
- Point out the joints to other trades
- Act on the first splits you see
Do not paint over the new sealant unless we’ve said the product is paintable. Paint can crack on a flexible joint.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal with no damage behind it to deal with.
What external mastic looks like in Hitchin
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Schools such as Hitchin Girls' School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s. Rented homes near Hitchin station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Hitchin is about 5 miles north-west of Stevenage, in Hertfordshire. Homes, rented property, offices and hotels in Hitchin is covered for external mastic. The work is guaranteed for a year. We cover 381 towns and villages across Hertfordshire. You can also see our page for London, roughly 32 miles from Hitchin.
Every address in SG4 and SG5 is covered for external mastic. External mastic is available to properties on Market Place, London Road and Harrison Close. Hitchin sits on or near the A505 and A600. Neighbouring places we cover for external mastic include Benslow (1 mile east), Poets Estate (1 mile east), Bearton (1 mile north-west), Walsworth (1 mile north-east) and Westmill (1 mile north-west). Further out, we also cover Stevenage (5 miles south-east), St Albans (14 miles south), Welwyn Garden City (11 miles south), Harpenden (10 miles south), Hatfield (13 miles south) and Hertford (13 miles south-east). Hitchin is one of the larger places we cover in Hertfordshire.
Local landmarks in Hitchin
Around Hitchin, our work takes us to homes and buildings near Highbury Infant School and Nursery, Butts Close and Kingshott School. Other local landmarks include Radcliffe Arms (less than half a mile north-east) and St Mary's Church (within half a mile south-west). There’s a railway station in Hitchin itself: Hitchin station. Well-known places in the area include Wymondley Castle (1.7 miles east) and Lister Hospital (3.1 miles south-east). For a walk, there’s Purwell Ninesprings and Markham's Hill.
When it isn’t the sealant
New sealant cannot fix everything, and we’d rather say so up front. Sealant won’t put right:
- Adding movement joints to masonry that has none
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cracks in the bricks or render themselves, away from the joints
If you are not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Surfaces we seal
- Copings & trims
- Joints between brick and frames
- Façade panels
- Render & cladding joints
- Concrete & block
- Brickwork movement joints