Hertfordshire · England
Markyate External Mastic
External mastic across Markyate and nearby, with every bit of old sealant taken out first and a one-year guarantee.
- Plants rooting in failed movement joints
- Gaps where render, brick and frames meet
- Joints with sealant missing in places
External mastic for homes and businesses in Markyate
Short cuts in external joints show up within a season or two. New sealant over old, joints packed with mortar and beads with no backing rarely last long. We strip the joint back and start again. We’re often asked to deal with plants rooting in failed movement joints and weathered mastic that no longer stretches, across façade panels, brickwork movement joints and render & cladding joints.
Homes around Markyate range from older cottages to newer houses, with walls and rooflines of every type. Older homes need their gutter and trim joints kept tight, newer ones their movement joints.
You get a 12-month guarantee, the same in Markyate as everywhere else we work.
- Place
- Markyate (AL3)
- Wider area
- Hertfordshire
- Cover
- One year on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How to look after the new joints
Good habits help new joints last longer. Our tips:
- Clear growth from the base of walls and joints
- Show decorators and builders where the movement joints are
- Ask before painting over external sealant
- Never let anyone fill a movement joint with mortar
Follow the cure time we give you before the joint is knocked or disturbed. Most exterior sealants skin fast but take longer to cure right through.
Small splits are the time to act. At that stage it’s a simple cut out and reseal with no damage behind it to deal with.
Also near Markyate
What else we do in Markyate
Honest limits
It helps to know what we cannot do too:
- Loose or hollow render, which needs re-rendering
- Cracked brickwork or render that needs a builder or plasterer
- Adding movement joints to masonry that has none
If you’re not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Joints and surfaces we work on
- Joints between brick and frames
- Concrete & block
- Brickwork movement joints
- Façade panels
- Render & cladding joints
- Copings & trims
Why deal with it now?
Resealing a run of joints in one go is generally better than patching one at a time. Joints of the same age tend to fail together, and access only has to be arranged once. In an older home around Markyate, damp from a failed joint can get into timber and plaster, and that’s a much bigger job than renewing the sealant.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, plus any working-time requirements on site. Ask us for a quote and we’ll go through it with you.
Why book with us
- Trusted Arbo and Everbuild sealants
- Domestic, commercial and hotel work
- Every job guaranteed for a year
- You choose the colour before work begins
Take a look at our cost guide or our reviews.
Markyate: your questions answered
Will you come out to Markyate?
Yes. Markyate is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
I let a flat near Luton Airport Parkway station. Can you help?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before work begins.
Can you seal joints between render and window frames?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. The colour is chosen to suit.
Are you ARBOMaster approved?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
When is the sealant fully cured?
Many sealants skin over quickly but take longer to cure fully. We will tell you how long to leave the joint.
Can you match the colour of my brickwork?
We aim for a joint that suits the wall rather than one that jumps out. Colour is agreed with you before we begin from the range available.
Can a movement joint be filled with mortar?
No. A mortar-filled joint can’t move, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
What information do you need?
Where the job is, what the problem is and roughly how big it is. Photos by email help too.
For landlords and businesses
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
DIY versus a professional finish
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
If you’re set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it does not work out, we can still put it right.
What external mastic looks like in Markyate
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.
In the older streets around Markyate Methodist Church, older walls, gutters and the joints where extensions meet them need a flexible sealant. Schools such as Markyate Village School and Nursery are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Luton Airport Parkway station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Markyate is in Hertfordshire. Every kind of property in Markyate is covered for external mastic, old or new, large or small. The work is guaranteed for a year. Markyate is one of 381 towns and villages in Hertfordshire we cover. You can also see our page for London, roughly 28 miles from Markyate.
We work across the AL3 postcode area for external mastic. That includes homes and businesses on High Street, London Road and Sebright Road and the roads around them. We also cover the places around Markyate: Roe End (1 mile south-west), Flamstead (2 miles south-east), Friar's Wash (2 miles south-east) and Trowley Bottom (2 miles south-east). We also work in nearby towns such as Watford (12 miles south), Hemel Hempstead (6 miles south), Stevenage (13 miles north-east), St Albans (8 miles south-east), Welwyn Garden City (12 miles east) and Harpenden (5 miles east).
What’s near Markyate
Locally, jobs take us to homes and businesses close to The Local pub. For rail, the closest station is Luton Airport Parkway station, roughly 3.8 miles north-east. Nearby you will also find Mossman Collection (2.6 miles north-east) and Luton Castle (3.3 miles north-east). For a walk, there’s Landpark Wood.
What happens on the day
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, carry out the job and clear up. It generally takes anything from a few hours to several days, depending on the building. A visit to Markyate is planned like any other: the time, the access and where to park are agreed in advance. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- We look at every joint and agree a colour to suit the wall.
- 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.
Before we arrive
- Let us know about stairs, lifts or work at height
- Tell us about any previous sealing or DIY attempts
- Mention any parking rules near the property
How to get a quote
There’s no standard price list, because every job is different. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or email us.
Read more
What affects the cost of external mastic
The quote reflects the job in front of us. We take into account:
- The number and length of the joints
- How many areas need sealing
- Whether there’s mould to deal with
- The product the joint needs
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please call 0345 464 0079 or email us and we will talk you through it.
What we need to know
When you contact us, these details help:
- The rough size of the job
- A few pictures by email, if you can
- Where the property is
- What the problem is, such as mould, gaps, leaks or cracking
To get a quote, phone 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You’ll have a clear quote before any work starts.