Hertfordshire · England
External Mastic in Felden
Specialist external mastic for Felden: careful preparation, the right product and tidy work. Call for a quick quote.
- Sealant pulling away from one side of the joint
- Failed seals between different materials
- Hard, crazed mastic that has stopped moving
How we handle external mastic in Felden
A movement joint is a deliberate break that lets a wall expand and contract. Its sealant has to flex with the building, season after season, so once it splits or hardens, the joint stops working and water gets in. Common call-outs are for panel joints letting water in and old sealant gone brittle and cracked, on render & cladding joints, brickwork movement joints and joints between brick and frames.
In and around Felden, older properties sit alongside newer ones, each with its own outside joints. Older gutters and trims need their joints resealed; newer brick and render need their movement joints kept sound.
We stand behind the work with a 12-month guarantee, so you’re covered after we have gone.
- Where
- Felden (HP3, WD4)
- Wider area
- Hertfordshire
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What happens if it’s left?
Running new sealant over the old bead rarely lasts. The new layer cannot bond properly to old, weathered material, so the old joint is cut out fully first. In an older home around Felden, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
What it costs depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. You’ll have a clear quote before any work starts, so you know where you stand.
Why Felden clients choose us
- Colour picked to suit the job
- Trusted Arbo and Everbuild sealants
- You choose the colour before work begins
- Approved under the ARBOMaster scheme
Read how sealant jobs are priced or our reviews.
For landlords and businesses
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance.
We also work for property managers and facilities teams in Felden and across Hertfordshire. We can quote a run of properties together.
DIY versus a professional finish
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so just mention it when you contact us.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Common problems we fix in Felden
If plants are growing out of a joint, the sealant has generally failed or was never there. Dirt and roots then trap moisture in the joint.
Any of these means the joints need attention:
- Failed seals between different materials
- Panel joints letting water in
- Movement joints with cracked, split or missing sealant
- Rain getting behind render or cladding at a joint
For landlords with property near Apsley station, outside joints that have cracked can let damp into a rental, so check them between lets.
Before you book anyone
- Which colour the sealant will be
- How hidden problems are handled
- What preparation is included
- How long the guarantee is
Towns and villages near Felden
What else we do in Felden
What affects the quote in Felden
Your quote is based on your job. We look at:
- When we can work, for business premises
- The number of rooms or windows
- How much old sealant there is and how hard it is to remove
- Access and height
Homes and businesses are quoted the same way: the amount of work, how we reach it and what it needs, plus any working-time requirements on site. Ask us for a quote and we will explain what it covers.
Asking for a quote
Before you ask for a quote, have a think about:
- A few pictures by email, if you can
- How we’d reach the joints
- The rough size of the job
- Whether it’s a home or a business
We quote each job on its own, so start by telling us what you need. Just ring 0345 464 0079 or drop us an email with the details.
How it works
Our applicators work methodically: protect, prepare, seal, tidy. For most jobs that takes a few hours for a handful of joints, longer for a whole elevation. Parking around Felden is usually 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.
- First we look over the joints with you, agree which to renew and talk through access.
- We cut out the failed sealant and rake out any dirt or growth.
- The joint faces are cleaned and primed where the sealant needs it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- For indoor joints, keep the area dry beforehand if you can
- Mention any leaks or damp you’ve noticed
Getting a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, ring 0345 464 0079 or send us an email.
Advice
External mastic in Felden: local notes
The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Felden is part of Hemel Hempstead, one of the post-war new towns. Many homes date from the post-war decades and were built in phases, so neighbouring houses often have rooflines and wall joints of the same age, wearing out at the same time.
If you look after a building such as Nash Mills Church of England Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. For an older house near a landmark such as Church of St Mary, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Felden is about 2 miles south of Hemel Hempstead, in Hertfordshire. Whether you are in the middle of Felden or further out, we cover external mastic for every kind of property, from flats and houses to offices and hotels. Felden is one of 381 places in Hertfordshire we cover for external mastic. We also work in London, around 22 miles away.
We cover every part of HP3 and WD4 for external mastic. We cover properties on Pond Road, Rose Lane and Lower Road and the roads around them. Other places close to Felden include Nash Mills (1 mile east), Rucklers Lane (1 mile south), Apsley (1 mile north-west), Bennetts End (1 mile north-east) and Kings Langley (1 mile south-east). We also work in nearby towns such as Watford (5 miles south-east), St Albans (6 miles east), Welwyn Garden City (12 miles east), Harpenden (8 miles north-east), Hatfield (10 miles east) and Borehamwood (9 miles south-east).
Local landmarks in Felden
Locally, jobs take us to homes and businesses close to Kings Langley School and The Paper Mill pub and the streets around them. Felden has its own railway station: Apsley station. Nearby you will also find Hemel Hempstead Hospital (1.5 miles north). For a walk, there’s Long Deans and Verulamium Lake.
Felden: your questions answered
Do older homes in Felden need their sealant replacing?
Often, yes: cracked, shrunken or mouldy sealant has done its job. The key is cutting all the old sealant out, as new sealant will not bond to it.
Will you come out to Felden?
Yes, Felden is covered. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Is the work guaranteed?
Yes, for a year. If anything isn’t right with the work within the year, let us know and we’ll sort it.
What’s an expansion joint in brickwork?
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 work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses, and we are fully insured.
Can landlords and businesses book you?
Yes, regularly. We can quote for several properties at once, and between tenancies is a good time for the work.
How much does external mastic cost in Felden?
Every job is different, so each one gets its own quote. To get one, phone 0345 464 0079 or send us an email and tell us what needs doing and where.
When is the sealant fully cured?
It depends on the product. We tell you how long to leave it before we go.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Ask before painting over external sealant
- Act on the first splits you see
- Do not let climbing plants root in the sealant
- Never let anyone fill a movement joint with mortar
Do not paint over the new sealant unless we’ve said the product is paintable. Many exterior sealants are not designed to be painted and spoil the finish.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage, all bigger jobs than a reseal.