Hertfordshire · England
Sand mastic for sash & case windows in Digswell, Hertfordshire
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Digswell and across Hertfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Gaps between timber frames and stone or brick
- Failed mastic on an exposed elevation
- Modern sealant on a period surround
Sand mastic in Digswell
Our applicators renew the sand mastic around sash and case windows and doors in stone and brick. The old mastic is raked out, and new mastic is applied and shaped by hand. If you’re dealing with wind and rain getting in round a sash window and weathered mastic on the most exposed windows, we can help.
Many houses in smaller places like Digswell have conservatories, garden rooms or patio doors. Those joints need the same attention as the main windows.
Our work is backed for twelve months, and the guarantee is the same wherever you are.
- Location
- Digswell (AL8, AL7, AL6)
- Wider area
- Hertfordshire
- Guarantee
- A year, on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
For landlords and businesses
For anyone letting property in or around Digswell, jobs at different addresses can go on one quote. Send us the addresses and the work at each.
We work for landlords and letting agents as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
What else we do in Digswell
What sand mastic looks like in Digswell
Welwyn Garden City, which Digswell is part of, was laid out as a garden city in the early twentieth century. Older garden city homes may still have timber windows, while many have been replaced over the years. Either way, the joint between frame and wall needs a sound bead. 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 frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
If you live in an older home near Digswell Village Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame. For landlords with property near Welwyn North station, older sash windows in a rental need their mastic kept sound to keep the weather out.
Digswell is about 1 mile north of Welwyn Garden City, in Hertfordshire. Anywhere in AL8, we cover sand mastic for homes and businesses. Digswell is one of 381 towns and villages in Hertfordshire where we work. You can also see our page for London, about 23 miles away.
Our applicators cover all of the AL8, AL7 and AL6 postcode area for sand mastic and the streets around it. If you need sand mastic at a property on Adele Avenue, Station Road and Hertford Road or anywhere close by, our applicators can take on the job. We also cover the places around Digswell: 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). Within a short drive, 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
We work in homes and buildings around 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). For a walk, there’s Tewin Orchard and Hopkyns Wood.
Do you need sand mastic in Digswell?
Most of it is simply age. Even well-laid mastic needs renewing in time and how long it lasts depends on the weather it faces.
Signs it’s time to call us include:
- Failed mastic on an exposed elevation
- Crumbling sand mastic round a window
- Wind and rain getting in round a sash window
- Modern sealant on a period surround
If you look after a building such as Harwood Hill Junior Mixed Infant and Nursery School, the mastic around its windows and doors needs looking after like any other building’s.
Comparing quotes
- How the joint is cleaned and prepared
- How the colour is chosen
- Whether they’re fully insured
- What happens if the job turns out different
How to look after the new joints
Once the sealant has cured, a few habits help it last:
- Have rotten timber repaired before new mastic goes in
- Find out about consent before window work on a listed home
- Keep sills and gutters clear so water drains away
- Look over the window mastic once a year
When preparing windows for paint, take care around the mastic. It can be damaged by heavy scraping.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
Should I try it myself first?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
Leave it or put it right?
If you’re redecorating, renew the mastic first. Paint over cracked mastic will not stop the gaps and traditional guidance is to leave the new mastic unpainted. Around Digswell, water from a failed joint in an older home can soak into timber and plaster, and that’s a much bigger job than renewing the sealant.
Combining jobs into one visit is usually more efficient than separate visits. You’ll get one clear quote for the whole job.
Why book with us
- 180+ five-star Google reviews
- Fully insured
- More than 20 years in sealant work
- An ARBOMaster approved applicator
See how sealant jobs are priced and our reviews.
What affects the quote in Digswell
Your quote is based on your job. We take into account:
- The product the joint needs
- Any working-time requirements on site
- The amount of work
- The old material and how stubborn it is
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and give you a clear price before we start.
What we need to know
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- What the problem is, such as mould, gaps, leaks or cracking
- Photos by email, if that is easy
- Access, such as stairs, a lift or height
- If it’s domestic, commercial or a hotel
We don’t publish a price list. Instead, we send you a clear quote for your job. To arrange one, phone 0345 464 0079 or email us.
Questions from Digswell
Do you work for landlords with property near Welwyn North station?
Yes, rental work is part of what we do. 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.
Is it worth replacing old sealant in an older home in Digswell?
In most cases, yes, if it hasn’t been done for a while. Sealant is a maintenance item: how long it lasts depends on use, cleaning and exposure, and many homes in Digswell may already be on their second or third set.
What exactly is sand mastic?
It’s a mix of sand and a linseed-oil-based binder. It’s built up in the joint by hand and finished to sit neatly against the masonry.
Are you ARBOMaster approved?
Yes. We’re an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
Is it possible to paint over sand mastic?
Sand mastic is normally left unpainted, which is what traditional guidance recommends. Ask us before decorating.
Do you cover Digswell?
We do. Digswell is part of the area we cover, and the service is the same as everywhere else.
Do I need to be at home?
That depends on where the joints are. Inside work needs someone to give us access, and for outside work we’ll agree access with you when we book.
What should I tell you?
Just the basics: the address or postcode, what’s wrong and any access issues. Then call 0345 464 0079 or drop us an email.
The process
There isn’t much for you to do on the day. Show us the job and we will take it from there. The job generally takes a few hours for a single window, longer for several from start to finish. 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.
- We check the window surrounds and agree which joints need renewing.
- Old, loose mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- The mastic is finished to sit tidily against the stone or brick.
Before we arrive
- Mention any sign-in or site rules at work premises
- Keep pets and children clear of the area while we work
- Move anything stored near the joints
How to get a quote
For a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before any work starts.