Hertfordshire · England
External Mastic in Hay Street
Professional external mastic in and around Hay Street, with old sealant always removed completely.
- Brick movement joints where the sealant has split
- Movement joints filled with mortar instead of sealant
- Gaps where render, brick and frames meet
About our external mastic in Hay Street
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 where a rigid filler would soon crack. If you’re dealing with joints where the bead has come unstuck and leaking joints around cladding and façade panels, we can put it right.
Somewhere as small as Hay Street, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Joints on those walls need a sealant that moves with the building and stays in place.
A 12-month guarantee comes as standard.
- Where
- Hay Street (SG11)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Price
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Common questions in Hay Street
What guarantee comes with external mastic in Hay Street?
Every job comes with our one-year guarantee, wherever it is. We’re fully insured, and an ARBOMaster approved applicator.
Will you come out to Hay Street?
Yes, smaller places are covered as well as towns. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do you use backing rod?
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.
When is the sealant fully cured?
Many sealants skin over quickly but take longer to cure fully. We’ll give you the cure time for the product we used.
Do you work for hotels and businesses?
Yes. We can plan bigger jobs in stages to suit the site.
What is a movement joint?
Walls move with heat, cold and moisture, and planned joints take up that movement. The gap is sealed with a flexible sealant over backing rod.
Do you have insurance?
Yes. We are fully insured, and we can confirm the details when we quote.
Can you match the colour of my brickwork?
The sealant colour is picked to suit the wall, so the joint sits quietly in the wall. There’s a wide choice of exterior colours.
When something else is needed
It helps to know what we can’t do:
- Render that’s blown, hollow or coming away
- Structural movement, which needs a surveyor or engineer
- Walls that need new movement joints cut into them
Not sure which it is? You can phone 0345 464 0079 or email us and we will tell you honestly.
Surfaces we seal
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Façade panels
- Render & cladding joints
- Concrete & block
Different surfaces, different methods
Render joints
Render is weaker at the surface than brick, so a sealant that stretches easily protects the edges. We prime where the product needs it.
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. We seal the joint with a flexible exterior sealant so neither cracks the other.
What happens if it’s left?
Mortar or ordinary filler might look like a quick way to close an open joint, but it locks the joint solid. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. Older cottages and farmhouses around Hay Street can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
The cost depends on the amount of work, how hard the old material is to remove and access to the work. You’ll have a clear quote before any work starts, so you know where you stand.
What you get with us
- Any old sealant cut out fully, not covered over
- More than 20 years in sealant work
- Colour agreed with you before we start
- Colour picked to suit the job
See what affects the cost and what customers say.
Aftercare tips
To keep the joints looking good and working properly:
- Check external joints each spring
- Avoid pressure-washing directly into sealant joints
- Leave the joints unpainted unless we’ve said otherwise
- Keep soil, plants and ivy away from the joints
Keep pressure washers away from the sealant. A strong jet can damage the edges of the bead.
Once a joint cannot move, the wall finds another way, normally as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.
Towns and villages near Hay Street
Other services in Hay Street
How the visit works
We keep the work tidy and contained to the area we’re working on, so you can carry on as normal. Expect the work to take a few hours to a few days, depending on the length of joint and the access, and we explain the cure time before we leave. For a village or hamlet like Hay Street, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Preparing for the visit
- Mention any leaks or damp you’ve noticed
- Plan for the work area to be out of bounds to pets and children
- Tell us about access, such as stairs, a lift or high-level joints
Get a quote
Need a quote? Please ring 0345 464 0079 or drop us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.
Advice
Hay Street buildings and the weather
Historic houses like Much Hadham Palace (about 4.7 miles south-east) are a reminder that the area around Hay Street 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. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Homes close to Parish Church of St Mary the Virgin include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep. Managing a site like Jenyns First School and Nursery? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Hay Street is about 7 miles north-west of Bishop's Stortford, in Hertfordshire. Our applicators cover external mastic for homes and businesses in Hay Street and nearby, as part of our work across Hertfordshire. Our area takes in 381 places across Hertfordshire, large and small. There’s also a page for Chelmsford, roughly 23 miles from Hay Street.
Jobs for external mastic in SG11 works the same way as everywhere else we cover. Other places close to Hay Street include Braughing (1 mile south-east), Westmill (2 miles west), Aspenden (2 miles north-west), Great Hormead (2 miles north) and Buntingford (3 miles north-west). Further out, we also cover Stevenage (9 miles west), Bishop's Stortford (7 miles south-east), Welwyn Garden City (12 miles south-west), Hitchin (13 miles west), Hoddesdon (11 miles south) and Cheshunt (15 miles south).
Around Hay Street
Locally, jobs take us to homes and businesses close to Adam And Eve Public House. Other landmarks nearby include Brent Pelham (3.7 miles north-east).
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
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, and the work is guaranteed for a year.
How we quote for external mastic
We don’t publish a price list. What we look at:
- How much there is to do
- Mould in or behind the old joints
- The product the joint needs
- Any working-time requirements on site
There are no prices on our website, because the cost depends so much on the job itself. For a quick quote, please ring 0345 464 0079 or send us an email.
What we need to know
When you call or email, it’s useful to know:
- Roughly how big the job is
- A few photos by email, if you can
- How we’d reach the joints
- What’s wrong with the joints now
For a quick quote, get us on the phone, or email us if that is easier. Tell us about the joints that need doing and we will talk you through the work and give you a clear quote.