Hertfordshire · England
External Mastic in Frithsden
Problem with your movement joints in Frithsden? We cut out the old, prepare the joints and apply the right sealant.
- Failed sealant between panels on a façade
- Damp patches traced to an open external joint
- Movement joints with cracked, split or missing sealant
Questions from Frithsden
Is Frithsden within the area you cover?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Is Frithsden in your area for external mastic?
Yes. We work across London and the South East, and Frithsden is part of that. You can call 0345 464 0079 or email us and let us know what needs doing.
Do you guarantee your work?
Yes. All our work carries our one-year guarantee.
Why do you put foam in the joint first?
We fit closed-cell backing rod wherever the joint depth needs controlling. It controls the depth and stops the sealant bonding to the back so the bead can stretch.
What do you need from me for a quote?
Let us know what needs doing and where. We’ll ask anything else we need to know.
Does someone need to be in?
We need access to the joints, so we will agree that with you when we book. For inside work, that normally means someone being in.
What colours does the sealant come in?
The aim is a neat, even joint in a colour that suits the wall. We will talk through colour options before we start, matched as closely as the range allows.
Will it make a mess?
We keep the work tidy. Nearby surfaces are protected.
How we handle external mastic in Frithsden
Getting the depth right is half the job. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, so it bonds to the two sides only and can stretch. If you have weeds or debris growing in open joints and damp patches traced to an open external joint, we can help.
External sealant needs dry, clean surfaces, so work around Frithsden is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
We stand behind the work with a one-year guarantee, so you are not left on your own once the job is done.
- Location
- Frithsden (HP1)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
How the visit works
At the end, we look at the finished work together and tell you how long to leave it. The visit itself normally takes a few hours to a few days, depending on the length of joint and the access, depending on how much there is to do. Somewhere like Frithsden needs a little journey planning: 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.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Getting ready for the visit
- Mention if the joints have been sealed before
- Let us know if you’ve seen damp or leaks
- For indoor joints, keep the area dry beforehand if you can
Getting a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email pictures if that is easy.
Advice
Looking after it afterwards
How long the joints last depends on use and care. Here’s what we suggest:
- Ask before painting over external sealant
- Never let anyone fill a movement joint with mortar
- Point out the joints to other trades
- Don’t let climbing plants root in the sealant
Only paint over the joint if we’ve confirmed the sealant can take paint. Many exterior sealants aren’t designed to be painted, and paint can crack as the joint moves.
A joint that has stopped moving pushes the movement elsewhere, often as cracks near the joint. Resealing it early helps prevent that.
When something else is needed
To be straight with you, some problems need a different trade:
- Loose or hollow render, which needs re-rendering
- Damp that isn’t coming from the joint
- Walls that need new movement joints cut into them
If you are not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Joints and surfaces we work on
- Brickwork movement joints
- Concrete & block
- Façade panels
- Joints between brick and frames
- Render & cladding joints
- Copings & trims
Why deal with it now?
A properly done movement joint is an even line in a colour that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner, so it pays to do it properly once. Where a wall is exposed, as many are in small places like Frithsden, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, any mould to treat, and whether the work is at height. Your quote takes all of that into account.
What you get with us
- Arbo and Everbuild products
- Anti-fungal sanitary silicone in wet areas
- We never seal over old sealant
- You choose the colour before work begins
See our cost guide and customer reviews.
Different surfaces, different methods
Brickwork movement joints
Brick moves with heat and moisture, and grows a little over time. The movement joint takes that up, so the sealant in it must stay soft and stretchy.
Concrete and blockwork
Wide joints in concrete need the depth controlling carefully. We size the backing rod to the gap and keep the sealant to the right depth.
For landlords and businesses
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Resealing at the right time is simple maintenance.
Walls and rooflines in Frithsden
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For an older house near a landmark such as Church of St Lawrence, an extension built onto an older house moves differently, and the joint between them takes the strain. Rented homes near Berkhamsted station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies. For site and facilities teams at buildings such as Potten End CofE Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Frithsden is about 2 miles north-east of Berkhamsted, in Hertfordshire. Across the HP1 area, our applicators can take on external mastic. We cover 381 towns and villages across Hertfordshire, large and small. There’s also a page for London, roughly 27 miles from Frithsden.
Work in HP1 works the same way as everywhere else we cover. Other places close to Frithsden include Nettleden (1 mile north-east), Potten End (1 mile south), Great Gaddesden (1 mile north-east), Fields End (1 mile south-east) and Ashridge (2 miles north-west). Larger places within reach include Watford (10 miles south-east), Hemel Hempstead (3 miles south-east), St Albans (9 miles east), Welwyn Garden City (14 miles east), Harpenden (8 miles east) and Hatfield (13 miles east).
Around Frithsden
Locally, jobs take us to homes and businesses close to John F Kennedy Catholic School and the streets around them. The closest station to Frithsden is Berkhamsted station, roughly 1.8 miles south-west. A little further out are Hawridge Court (4.9 miles south-west) and Hemel Hempstead Hospital (3.1 miles south-east). The countryside around Frithsden includes Long Deans.
Can I do it myself?
If you’re 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 fails, we can still redo it.
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.