Hertfordshire · England
External & façade joints in King's Walden, Hertfordshire
External mastic in King's Walden from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Joints where the bead has come unstuck
- Gaps where render, brick and frames meet
- Joints pointed up with cement by mistake
Common questions in King's Walden
Do you work for landlords with property near Luton Airport Parkway station?
Yes, we work for landlords and letting agents. You can call 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before work begins.
Is King's Walden within the area you cover?
Yes, we do. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
How long will you be here?
As a guide, most jobs take a few hours to a few days, depending on the length of joint and the access. Larger jobs naturally take longer, and we will tell you how long to expect.
Do you do commercial work?
Yes. Hotels, offices and other businesses use us.
What colours does the sealant come in?
We choose a sealant colour to suit the brick, stone or render, so the joint sits quietly in the wall. Exterior sealants come in a good range of colours.
What is backing rod for?
That’s backing rod, a closed-cell foam. It stops the sealant going in too deep and bonding to three sides, which would stop it stretching.
Can you reach joints on upper floors?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher ones, send details and we’ll confirm the access.
How long does external mastic last?
There’s no fixed answer: sunny, exposed elevations and busy joints wear faster. A yearly look will tell you when they need doing. Every job carries our one-year guarantee.
About our external mastic in King's Walden
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant in a colour to suit. Typical jobs include movement joints filled with mortar instead of sealant and leaking joints around cladding and façade panels, on copings & trims, brickwork movement joints and render & cladding joints.
Older homes in small places like King's Walden may be stone, brick or timber-framed, often with later extensions. Where one material meets another is where water generally gets in.
Each job carries a 12-month guarantee, whatever its size.
- Place
- King's Walden (SG4)
- Wider area
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Looking after it afterwards
Joint life depends on how it’s used and looked after. We suggest:
- Don’t let climbing plants root in the sealant
- Check the sealant is paintable before painting near it
- Avoid pressure-washing directly into sealant joints
- Keep movement joints as flexible joints, not mortar
Do not paint over the new sealant unless we’ve said the product is paintable. Paint can crack on a flexible joint and spoil the finish.
Gaps, plants or missing sealant in a joint are worth getting looked at. Earlier resealing means a smaller job and a better result.
Why act early in King's Walden
A failed movement joint lets water into the wall, behind render and cladding. Resealing early keeps the job to the joint itself, instead of the wall and finishes around it. In a small place like King's Walden, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
The cost reflects the work involved, not guesswork. That’s why we ask a few questions first and give you a clear price before work begins.
Why King's Walden customers choose us
- 4.9 on Google from 180+ five-star reviews
- We never seal over old sealant
- White, clear, grey or another colour, product permitting
- ARBOMaster approved applicator
Take a look at our cost guide and our reviews.
What we do, step by step
On the day, there’s very little for you to do. Point us to the joints and we will 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 village or hamlet like King's Walden, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Getting ready for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Clear items away from the joints we are working on
- Mention any leaks or damp you’ve noticed
How to get a quote
There’s no standard price list, because every job is different. Instead, we give you a clear quote for your job. To get started, call 0345 464 0079 or drop us an email.
Read more
Different surfaces, different methods
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. We cut out the old sealant and reseal with a product suited to both surfaces.
Render joints
Rendered walls have joints at beads, openings and changes of material. We reseal them with a flexible exterior sealant that suits the render colour.
Honest limits
A few problems are outside what sealant work can do:
- Subsidence or other structural problems
- Walls that need new movement joints cut into them
- Rising or penetrating damp from elsewhere in the wall
Not sure which it is? You can phone 0345 464 0079 or email us and we’ll tell you honestly before booking.
What we seal
- Façade panels
- Render & cladding joints
- Brickwork movement joints
- Copings & trims
- Concrete & block
- Joints between brick and frames
Outside joints around King's Walden
Historic houses like Knebworth House (about 4.7 miles south-east) are a reminder that the area around King's Walden has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. 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.
If you let a flat or house near Luton Airport Parkway station, split movement joints are easy to miss on a rental until damp shows inside. Homes close to Church of St Mary include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep. For site and facilities teams at buildings such as Breachwood Green Junior Mixed and Infant School, its movement joints, gutters and trims need looking after like any other building’s.
King's Walden is about 4 miles south-west of Hitchin, in Hertfordshire. If you need external mastic in King's Walden, please call 0345 464 0079 or send us an email for a quick quote. We’re based in Crawley and cover Hertfordshire. King's Walden is one of 381 towns and villages in Hertfordshire where we work for external mastic. We also work in London, about 29 miles from King's Walden.
All of SG4 is within our area for external mastic, from the main roads to the quietest streets. Nearby, we also carry out external mastic in The Heath (1 mile south-west), Breachwood Green (1 mile south-west) and Bendish (1 mile south). Within a short drive, we also cover Hemel Hempstead (12 miles south-west), Stevenage (6 miles east), St Albans (10 miles south), Welwyn Garden City (9 miles south-east), Harpenden (6 miles south) and Hitchin (4 miles north-east).
Landmarks near King's Walden
For rail, the closest station is Luton Airport Parkway station, about 3.9 miles south-west. Nearby you’ll also find North Hertfordshire Museum (3.8 miles north-east) and Wymondley Castle (4.6 miles north-east). For a walk, there’s Markham's Hill and Oughtonhead Nature Reserve.
Places near King's Walden
More services for King's Walden
Landlords, agents and businesses in King's Walden
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
Should I try it myself first?
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.