Hertfordshire · England
External & façade joints in Shenley, Hertfordshire
Sealing brickwork movement joints, render, cladding and façade joints for Shenley, backed by a 12-month guarantee. Call for a quick quote.
- Panel joints letting water in
- Old sealant gone brittle and cracked
- Cracked joints where brick meets render or frames
What affects the cost of external mastic
You’ll get a clear quote before we start. It takes into account:
- Mould in or behind the old joints
- How much there is to do
- Working hours on commercial sites
- How many rooms, windows or areas are involved
Combining jobs into one visit normally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
Asking for a quote
When you contact us, these details help:
- Any access issues, like height or stairs
- What the problem is, such as mould, gaps, leaks or cracking
- Where the property is
- Whether it’s a home or a business
Every job is quoted individually, so the first step is telling us about yours. Simply call 0345 464 0079 or email us and describe the job and send pictures if you have them.
How we handle external mastic in Shenley
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product in a colour to suit. We are often asked to deal with sealant that has lost its bond to the brick or render and hard, crazed mastic that has stopped moving, on render & cladding joints, façade panels and brickwork movement joints.
Homes around Shenley 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.
The work is covered for a year after we finish. If anything is not right with it, phone 0345 464 0079 or email us.
- Where
- Shenley (WD7)
- Region
- Hertfordshire
- Cover
- One year on every job
- Price
- A clear price before work begins
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
DIY sealant or a professional job?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly.
What we can’t put right
We will not take on work that will not last, so these are the limits:
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Cutting new joints into brickwork, which is building work rather than sealant work
- Subsidence or other structural problems
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think before you book.
What we seal
- Concrete & block
- Façade panels
- Copings & trims
- Brickwork movement joints
- Render & cladding joints
- Joints between brick and frames
Outside joints around Shenley
With historic houses such as Wyllyotts Manor (about 4.1 miles east) nearby, there’s older building stock in the area around Shenley as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
If you let a flat or house near Radlett station, outside joints that have cracked can let damp into a rental, so check them between lets. Schools such as Shenley Primary School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing. If you live in an older home near Church of St Martin, old and new materials meet at the roofline and walls, which is where sealant earns its keep.
Shenley is about 2 miles north of Borehamwood, in Hertfordshire. Whether you are in the middle of Shenley or further out, external mastic is available for homes and businesses alike. Our Hertfordshire coverage runs to 381 places, and Shenley is one of them. You can also see our page for London, roughly 16 miles from Shenley.
Jobs for external mastic in WD7 works the same way as everywhere else we cover. We cover properties on London Road, Southerton Way and Juniper Gardens. You will find Shenley on the B5378, which makes it straightforward to reach. Nearby, we also carry out external mastic in Green Street (1 mile south-east), Ridge (2 miles east), Well End (2 miles south-east), Borehamwood (2 miles south) and South Mimms (2 miles east). We also work in nearby towns such as Watford (5 miles south-west), Hemel Hempstead (8 miles north-west), St Albans (4 miles north-west), Welwyn Garden City (8 miles north-east), Harpenden (9 miles north) and Hoddesdon (12 miles east).
Around Shenley
Locally, jobs take us to homes and businesses close to Manor Lodge School, Hertswood Academy and The Black Lion pub, among other places. The nearest railway station is Radlett station, about 1.4 miles south-west. Well-known places in the area include Radlett and District Museum (1.5 miles south-west) and Shenley Hospital (less than half a mile west). Open spaces near Shenley include Verulamium Lake and Broad Colney Lakes.
Leave it or put it right?
A properly done movement joint is an even line in a colour that suits the wall. A rushed bead with no backing looks untidy and does not last, so it pays to do it properly once. Homes in smaller places like Shenley can face more weather, and failed outside joints let damp into walls. Indoors, a failed seal lets water into floors and panels as it would anywhere.
What you pay reflects the work, not a rough estimate. That is why we ask a few questions first.
Why book with us
- 12-month guarantee on every job
- You choose the colour before work begins
- Sanitary silicone with an anti-fungal additive in wet areas
- We never seal over old sealant
Read our cost guide and our reviews.
What the job involves on each surface
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind and protects the render itself.
Concrete and blockwork
Big joints in concrete need careful depth control. We size the backing rod to the gap so the sealant is not too deep.
Questions from Shenley
Do you cover smaller places like Shenley?
Yes, Shenley is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
I let a flat near Radlett station. Can you help?
Yes. We work for letting agents and landlords as well as householders, and several properties can be quoted together. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Will the old sealant be removed?
Yes. We cut out all the old sealant and clean the joint.
Can new sealant go over the old?
No. New silicone won’t bond to old silicone, and it traps any mould or water underneath. We remove it all first.
How much does external mastic cost in Shenley?
Size, access and the old material all affect the cost. Ask us for a quote.
How long before the joint can be used?
That depends on the sealant used, so follow the cure time we give you.
Can a movement joint be filled with mortar?
No. Cement or mortar can’t stretch. Where a joint has been mortared, it can often be raked out and sealed properly.
Will there be a smell?
There can be a smell while the sealant cures, which fades as it sets. Ventilation helps.
How the visit works
Once we are on site, we check the joints match what you told us. If anything is different, we explain it before carrying on. Most jobs then take anything from a few hours to several days, depending on the building. Parking around Shenley is normally easier than in a town centre, but mention any lanes, gates or long drives. For outside work, side access and the height of the joints help us plan.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- The old mastic and anything lodged in the joint is removed.
- 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.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Preparing for the visit
- Clear the area around the work
- Tell us if parking is tricky
- Let us know if you’ve seen damp or leaks
Ask for a quote
There’s no standard price list. Instead, we give you a clear quote for your job. To get started, ring 0345 464 0079 or drop us an email.
Advice
Nearby places to Shenley
Other services in Shenley
Looking after it afterwards
A little care helps the new joints last. We recommend:
- Walk round the building once a year and look at the joints
- Get split or bare joints resealed while the damage is small
- Leave the joints unpainted unless we have said otherwise
- Keep movement joints as flexible joints, not 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.
An open movement joint lets rain into the wall every time it pours. Over time it can mean damp inside, stained render or frost-damaged brick which cost more to put right than the joint.