Hertfordshire · England
Sand mastic for sash & case windows in Stevenage, Hertfordshire
We cover Stevenage for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old sealant removed completely, joints prepared properly.
- Mastic that needs renewing before redecorating
- Cracked mastic round a front door frame
- Cement or filler used on old window joints that has cracked
About our sand mastic in Stevenage
Sand mastic suits most period window surrounds. Newer frames usually get a flexible sealant instead, and we’ll talk through which suits your home. We work on tenement windows, timber door frames and period & listed homes, and the jobs we see most are old sand mastic that has cracked, crumbled or fallen out and gaps between timber frames and stone or brick.
A place the size of Stevenage has every kind of window, from older timber frames to uPVC and aluminium in newer homes. Each needs the right sealant, and each joint wears out eventually.
Big or small, you get the same 12-month guarantee in Stevenage and across Hertfordshire.
- Where
- Stevenage (SG1, SG2, SG3)
- Region
- Hertfordshire
- Guarantee
- One year on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
How to look after the new joints
Joint life depends on how it’s used and looked after. We suggest:
- Clear gutters so water does not pour onto the windows
- Keep modern sealant off the mastic
- Check the mastic when you check the paintwork
- Go gently near the mastic when preparing windows
When preparing windows for paint, take care around the mastic. It can be damaged by heavy scraping.
Gaps round a sash box let in draughts and rain. The longer it’s left, the more the joint opens.
Towns and villages near Stevenage
What else we do in Stevenage
What happens on the day
There isn’t much for you to do on the day. Point us to the joints and we’ll get on with it. The job generally takes a few hours per window, depending on the condition of the joints. Commercial jobs in Stevenage can be planned out of hours where a building cannot close, and homes are booked within our usual hours, Monday to Saturday.
- First we agree which joints need doing.
- We remove the old, loose mastic.
- Deep gaps are packed so the mastic sits at the right depth.
- We apply the mastic by hand and shape it.
- The surface is finished to suit the stone or brick.
Preparing for the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know about parking restrictions
- Keep children and pets away from the work area
Getting a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is. When it suits you, ring 0345 464 0079 or drop us an email.
Read more
What sealant work can’t fix
Some problems need a builder, plumber or other trade rather than us:
- Whether work needs listed building consent
- Damaged stone surrounds
- Sashes that need overhauling
Not sure which it is? You can ring 0345 464 0079 or email us and we’ll tell you honestly before you book.
Surfaces we seal
- Period & listed homes
- Brick reveals
- Stone surrounds
- Sash and case windows
- Timber door frames
- Tenement windows
Stevenage questions
Is it worth replacing old sealant in an older home in Stevenage?
If it hasn’t been replaced for some years, it’s normally worth it. Sealant is a maintenance item: how long it lasts depends on use, cleaning and exposure, and many homes in Stevenage may already be on their second or third set.
Do you work for landlords with property near Stevenage station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Is there any odour?
Sometimes, a little. It fades as the sealant cures, and ventilation helps.
Can I add another job to the visit?
Yes. Tell us about everything you’d like done and you will get one quote.
Do I need permission for sand mastic on a listed building?
It’s best to ask your local planning authority first. Like-for-like sand mastic is often the preferred finish but the decision is theirs.
Should I use sand mastic or silicone?
It depends on the window. Period windows in stone or brick normally suit sand mastic and newer frames normally get a flexible sealant.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and anything trapped underneath, including mould and water, stays there. It all has to come out first.
Do you cover Stevenage?
We do. Stevenage is part of the area we cover.
How the job changes by surface
Tenement and terrace windows
Windows above ground floor need the right access. Let us know the floor and we’ll confirm access.
Sash and case windows
The mastic round a sash window is on show, so a neat, even finish matters.
For landlords and businesses
Housing providers, facilities teams and property managers book us too in Stevenage and across Hertfordshire. We can quote a run of properties together.
Failed sealant is one of the commonest items on a check-out report, and it’s easy to sort out between tenants. Several properties can be quoted together.
Leave it or put it right?
Before painting the windows, it pays to renew the mastic. Paint over cracked mastic won’t stop the gaps and traditional guidance is to leave the new mastic unpainted. In a busy place like Stevenage, a failed joint in a flat or office can send water into the space below, where it’s often found late and is bigger to put right.
The cost reflects the work involved, not guesswork. That is why we ask a few questions first.
Why us?
- More than 20 years in sealant work
- Sanitary silicone with an anti-fungal additive in wet areas
- We never seal over old sealant
- A 12-month guarantee on all work
Take a look at how sealant jobs are priced or customer reviews.
Common problems we fix in Stevenage
Water gets into small cracks in the mastic and pushes it out. Exposed elevations normally fail first.
Most people get in touch when they notice something like this:
- Mastic round period door frames that has failed
- Cement or filler used on old window joints that has cracked
- Wind and rain getting in round a sash window
- Modern sealant on a period surround
Managing a site like Saint Vincent de Paul Catholic Primary School? Then larger buildings have plenty of frames, and the mastic around each one ages.
What your quote should include
- Are they insured?
- How the surfaces are prepared before sealing
- When the joint can take water or movement
- Is the old sealant removed completely?
Stevenage homes and the weather
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. With historic houses such as Aston Bury (about 2.5 miles south-east) nearby, there’s older building stock in the area around Stevenage as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
If you live in an older home near St Hugh & St John, frames set in older brick or stone need a sealant that suits the wall as well as the frame. Letting a property close to Stevenage station? Then older sash windows in a rental need their mastic kept sound to keep the weather out.
Stevenage is about 26 miles east of Milton Keynes, in Hertfordshire. Homes, rented property, offices and hotels in Stevenage is covered for sand mastic, old or new, large or small. The work is guaranteed for a year. Our area takes in 381 places across Hertfordshire, large and small. There’s also a page for London, roughly 29 miles from Stevenage.
Postcode districts we cover here for sand mastic: SG1, SG2 and SG3. If you need sand mastic at a property on King Pin Square, Market Square and Market Place or a nearby road, our applicators can take on the job. Being close to the A602 and B197, Stevenage is easy for our applicators to reach. We also cover Bedwell (1 mile south-west), Pin Green (1 mile north-west), Chells (1 mile east), St Nicholas (1 mile north) and Rooks Nest (1 mile north). Within a short drive, we also cover St Albans (13 miles south-west), Bishop's Stortford (15 miles east), Welwyn Garden City (8 miles south), Harpenden (10 miles south-west), Hitchin (5 miles north-west) and Hoddesdon (13 miles south-east). Stevenage is among the bigger towns we cover in Hertfordshire.
Landmarks near Stevenage
In Stevenage, that means homes and buildings near The Heathcote School, Church of Saint Nicholas and Marriotts School, among other places. The closest station to Stevenage is Stevenage station, roughly 1.2 miles south-west. A little further out are Benington Castle (2.9 miles east) and Stevenage Museum (0.8 miles south-west). Open spaces near Stevenage include Pryor's Wood.