Hertfordshire · England
External Mastic in Digswell
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Digswell and across Hertfordshire. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Weathered mastic that no longer stretches
- Cracked joints where brick meets render or frames
- Joints where the bead has come unstuck
External mastic in Digswell, done properly
Failed sealant is cut out, the depth set with closed-cell backing rod, and the joint resealed with a low-modulus sealant made for outside. We pick a colour that sits well with the wall. We work on joints between brick and frames, concrete & block and façade panels, and people most often call us about plants rooting in failed movement joints and movement joints with cracked, split or missing sealant.
Around Digswell, garages, outbuildings and extensions all add to the joints on the outside of a home. Leaks normally start at a gutter end, a garage door frame or where an extension meets the house.
All of our work is guaranteed for twelve months, in Digswell and everywhere else we cover.
- Location
- Digswell (AL8, AL7, AL6)
- Wider area
- Hertfordshire
- Cover
- A year, on every job
- Quote
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Check external joints each spring
- Tell anyone working on the walls about the movement joints
- Ask before painting over external sealant
- Wash walls gently around the sealant
Give the sealant the cure time we tell you before anything rubs against it. The surface skins over quickly, but full cure takes longer.
Act while the splits are small. Then it’s a straightforward cut-out and reseal.
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.
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.
Towns and villages near Digswell
Also in Digswell
Honest limits
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Failed render or damaged cladding panels
- Cracked brickwork or render that needs a builder or plasterer
- Adding movement joints to masonry that has none
If you are not sure, just ring 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Surfaces we seal
- Copings & trims
- Concrete & block
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Joints between brick and frames
Common questions in Digswell
Is Digswell within the area you cover?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Is it worth replacing old sealant in an older home in Digswell?
Normally, yes, if it’s cracked, shrunk, mouldy or coming away. The key is cutting all the old sealant out, as new sealant will not bond to it.
Is the work guaranteed?
Yes. All our work carries our 12-month guarantee.
Do you take out the old sealant first?
Yes, every time. New sealant won’t bond properly to old, so the joint is cleaned back first.
Will it make a mess?
No. The area is protected while we work and cleaned up afterwards.
How long does external mastic take?
A typical job takes anything from a few hours to several days, depending on the building, including preparation and clearing up. Your quote will say how long we expect yours to take.
Is it OK to fill a movement joint with cement?
No. A mortar-filled joint can’t move, so the movement cracks the wall elsewhere. Use a flexible sealant with backing rod.
Do you work at height?
It depends on the building. Tell us the height, the number of joints and what’s below them, and we will confirm what access is needed.
Outside joints around Digswell
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. With historic houses such as Digswell House (about 0.3 miles west) nearby, there’s older building stock in the area around Digswell as well as newer homes. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
Managing a site like Harwood Hill Junior Mixed Infant and Nursery School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Welwyn North station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Digswell is about 1 mile north of Welwyn Garden City, in Hertfordshire. Whether you are in the middle of Digswell or further out, external mastic is available for homes and businesses alike. Digswell is one of 381 places in Hertfordshire we cover for external mastic. For nearby work, see our London page (23 miles or so).
Our applicators cover all of the AL8, AL7 and AL6 postcode area for external mastic. If you need external mastic at a property on Adele Avenue, Station Road and Hertford Road or anywhere close by, we can help. Other places close to Digswell include Haldens (1 mile south-east), Harmer Green (1 mile north-east), Burnham Green (2 miles north-east), Oaklands (2 miles north) and Tewin (2 miles east). Further out, we also cover Watford (14 miles south-west), Hemel Hempstead (12 miles west), Stevenage (6 miles north), St Albans (7 miles south-west), Harpenden (6 miles west) and Hitchin (10 miles north).
Landmarks near Digswell
Typical jobs here are in homes near Hedgehog pub, Monk's Walk School and Danesbury Park and the streets around them. There’s a railway station in Digswell itself: Welwyn North station. Well-known places in the area include Howard Centre (1.3 miles south) and Datchworth Museum (2.6 miles north-east). Green spaces nearby include Tewin Orchard and Hopkyns Wood.
Do you need external mastic in Digswell?
UV, rain and frost all age exterior sealant. Over the years it hardens, cracks on the surface and loses its give, so the joint eventually tears or comes away from one side.
Most people get in touch after spotting something like this:
- Moss and dirt in joints with no sealant left
- Joints with sealant missing in places
- Old sealant gone brittle and cracked
- Rigid filler in a joint that should flex
For an older house near a landmark such as Digswell Village Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
What your quote should include
- What insurance they hold
- What preparation is included
- Whether VAT is included
- What product goes in the joint
Landlord and commercial work in Digswell
Housing providers, facilities teams and property managers book us too in Digswell and across Hertfordshire. Several sites can go on one quote, and we’re fully insured.
From a single let to a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Should I try it myself first?
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly.
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
How the visit works
Every visit runs the same way: we look at the joints together, protect the area around them, do the work and clear up. Most jobs take a few hours for a handful of joints, longer for a whole elevation. In a smaller place like Digswell, parking is seldom the issue; lanes, gates and long drives are worth mentioning. For outside work, side access and the height of the joints help us plan.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
How to prepare
- Clear the area around the work
- Keep pets and children clear of the area while we work
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved before giving you a price.