Hertfordshire · England
External Mastic in Friar's Wash
Specialist external mastic for Friar's Wash: the right sealant, proper preparation and a neat finish. Ask us for a quick quote.
- Sealant pulling away from one side of the joint
- Old sealant gone brittle and cracked
- Moss and dirt in joints with no sealant left
External mastic in Friar's Wash, done properly
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two. We work on concrete & block, render & cladding joints and façade panels, and the jobs we see most are joints with sealant missing in places and water getting into walls through failed joints.
Around Friar's Wash, older buildings can be stone, brick or timber-framed, many with extensions added later. Where one material meets another is where water normally gets in, and they need the right sealant at the right depth.
You are covered for a year from the day we finish. If anything is not right with it, phone 0345 464 0079 or email us.
- Place
- Friar's Wash (AL3)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
What external mastic looks like in Friar's Wash
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Childwickbury Manor (about 4.5 miles south-east) are a reminder that the area around Friar's Wash has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
If you let a flat or house near Harpenden station, split movement joints are easy to miss on a rental until damp shows inside. Homes close to Church of St Leonard include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Friar's Wash is about 3 miles west of Harpenden, in Hertfordshire. Wherever you are in the AL3 postcode area, we can carry out external mastic at your property. Our Hertfordshire coverage runs to 381 places, Friar's Wash among them. There’s also a page for London, about 27 miles away.
We work across AL3 for external mastic. You’ll find streets such as London Road, Chequers Hill and Old Watling Street. If you are just outside Friar's Wash, we cover Flamstead (1 mile south-west), Trowley Bottom (1 mile south-west) and Markyate (2 miles north-west). Within a short drive, we also cover Watford (11 miles south), Hemel Hempstead (5 miles south), Stevenage (12 miles north-east), St Albans (7 miles south-east), Welwyn Garden City (10 miles east) and Harpenden (3 miles east).
Local landmarks in Friar's Wash
Typical jobs here are in homes near Chequers pub and Roundwood Park School. Friar's Wash’s nearest station is Harpenden station, about 3.2 miles east. Other landmarks nearby include Luton Castle (3.5 miles north) and Redbourn Museum (2.3 miles south-east). Open spaces near Friar's Wash include Landpark Wood.
Nearby places to Friar's Wash
What else we do in Friar's Wash
How it works
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 anything from a few hours to several days, depending on the building, including the tidy-up. Somewhere as small as Friar's Wash, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We look at every joint and agree a colour to suit the wall.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Let us know about stairs, lifts or work at height
- On commercial sites, let us know about site rules
- Let us know if you’ve seen damp or leaks
Get a quote
To get a quote, call 0345 464 0079 or send 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.
Read more
Landlord and commercial work in Friar's Wash
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.
If you manage several properties in or around Friar's Wash, several properties can be quoted together. Just tell us the addresses and what each one needs.
When to call us in Friar's Wash
Sunlight, wet weather and frost wear exterior sealant down. Over the years it hardens, cracks on the surface and loses its give, so the next time the wall moves, it splits or pulls away.
Common reasons people contact us include:
- Rigid filler in a joint that should flex
- Joints with sealant missing in places
- Cracked joints where brick meets render or frames
- Hard, crazed mastic that has stopped moving
For site and facilities teams at buildings such as Flamstead Village School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Questions to ask before you book
- How the colour is chosen
- Whether the sealant suits the joint
- What the quote includes, VAT included or not
- Whether all the old sealant comes out first
Honest limits
We will always be straight with you, so here’s what new sealant won’t do:
- Failed render or damaged cladding panels
- Rising or penetrating damp from elsewhere in the wall
- Walls that need new movement joints cut into them
Not sure which it is? You can call 0345 464 0079 or drop us an email and we will tell you honestly before booking.
Surfaces we seal
- Joints between brick and frames
- Brickwork movement joints
- Render & cladding joints
- Copings & trims
- Concrete & block
- Façade panels
DIY sealant or a professional job?
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
A careful DIYer can reseal a simple joint, 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.
Keeping the joints in good condition
Aftercare is simple, and it makes a real difference:
- Tell anyone working on the walls about the movement joints
- Leave the joints unpainted unless we’ve said otherwise
- Wash walls gently around the sealant
- Look over the joints every year, ideally after winter
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
How the job changes by surface
Brickwork movement joints
Vertical joints in long brick walls let the brickwork expand without cracking. We reseal them with a low-modulus sealant over backing rod coloured to suit the wall.
Concrete and blockwork
The face of concrete or block is often dusty, so cleaning and priming matter. We prime where the sealant needs it.
FAQs for Friar's Wash
Is Friar's Wash in your area for external mastic?
Yes, Friar's Wash is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or send us an email and let us know what needs doing, and we will give you a clear quote.
Do you work for landlords with property near Harpenden station?
Yes, we work for landlords and agents. You can ring 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before any work starts.
Can you do several jobs on one visit?
Yes. More than one area can be quoted together.
How long should I leave it?
Most sealants are touch-dry well before they’re fully cured. We’ll give you the cure time for the product we used.
Do you work at height?
It depends on the height and the site. Low-level joints are straightforward; for higher ones, send details and we will confirm the access.
What is a movement joint?
Most straight vertical gaps in brickwork are movement joints. It lets the bricks expand without cracking, and it should be sealed with a flexible sealant.
What do you need from me for a quote?
Where the job is, what the problem is and roughly how big it is. Photos by email help too.
Can you seal over the old sealant?
No. Fresh sealant doesn’t stick to old sealant, and it traps any mould or water underneath. It all has to come out first.