Hertfordshire · England
Stevenage Window Mastic
Window mastic for Stevenage, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Cracked or shrunken mastic around the frame
- Sealant in the wrong colour for the frame
- Draughts coming in around windows and doors
Honest limits
We will always be straight with you, so here’s what sealant can’t fix:
- Broken hinges, locks or handles
- Damp problems in the wall away from the window
- A frame that has rotted at the joint
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we will tell you honestly before you book.
Surfaces we seal
- Aluminium frames
- Timber windows & doors
- Patio & French doors
- Window sills
- uPVC windows
- Composite doors
About our window mastic in Stevenage
Around Stevenage we seal all kinds of frames: uPVC, aluminium, timber and composite, along with patio doors, French doors and sills. Each gets a sealant chosen for the frame and the wall it meets. Common call-outs are for mastic that has split away from the wall and cracked sealant at the sill ends, across window sills, patio & French doors and uPVC windows.
In Stevenage, windows range from older timber frames to modern uPVC and aluminium. Each needs the right sealant, and each joint wears out eventually.
You are covered for a year from the day we finish. If there’s a problem with it, please call 0345 464 0079 or drop us an email.
- Location
- Stevenage (SG1, SG2, SG3)
- Wider area
- Hertfordshire
- Cover
- A year, on every job
- Quote
- A clear price before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
How to look after the new joints
Aftercare is simple:
- Ventilate rooms so frames don’t stay wet inside
- Clean frames with a soft cloth and soapy water
- Don’t paint over the silicone
- Avoid blasting the frames with a pressure washer
On timber frames, keep the paintwork in good order, because bare, wet timber moves more and pulls at the joint. Paint up to the joint, not over the silicone.
Draughts get worse, not better. As old mastic keeps shrinking, the gap widens, and a cold room gets colder. A new joint closes it up.
Why deal with it now?
The work is quick compared with the damage it prevents: the visit takes a morning for a couple of windows and a door. Leave it until water is coming in and you may need plastering and decorating as well. For landlords in Stevenage, failed sealant soon turns into tenant complaints about mould, damp or draughts. It’s simpler to sort between tenants than in the middle of a let.
What you pay reflects the work, not a rough estimate. That is why we ask a few questions first.
What you get with us
- More than 20 years in sealant work
- Approved under the ARBOMaster scheme
- Sealant colour chosen to suit
- White, clear, grey or another colour, product permitting
Take a look at how sealant jobs are priced or customer reviews.
Stevenage homes and the weather
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Stevenage is one of the post-war new towns. Many homes date from the post-war decades, and many will have had their original windows replaced. That mastic ages as well, and sills and frame heads are where leaks start.
In the older streets around St Hugh & St John, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. If you look after a building such as Saint Vincent de Paul Catholic Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Stevenage is about 26 miles east of Milton Keynes, in Hertfordshire. We provide window mastic to homes and businesses in Stevenage and nearby. Across Hertfordshire, we cover 381 places, Stevenage among them. There’s also a page for London, about 29 miles away.
All of SG1, SG2 and SG3 is within our area for window mastic, from the main roads to the quietest streets. Local streets include King Pin Square, Market Square and Market Place, and we cover them all. Being close to the A602 and B197, Stevenage is simple for us to get to for window mastic. Close by, we work in 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.
Local landmarks in Stevenage
Around Stevenage, our work takes us to homes and buildings near The Heathcote School, Church of Saint Nicholas and Marriotts School, among other places. For rail, the closest station is Stevenage station, about 1.2 miles south-west. Other landmarks nearby include Benington Castle (2.9 miles east) and Stevenage Museum (0.8 miles south-west). Green spaces nearby include Pryor's Wood.
Do you need window mastic in Stevenage?
On timber frames, paint and putty build up around the joint. Mastic painted over many times cracks with the paint, and timber moves with moisture as well as temperature.
The most common problems we see are:
- Whistling draughts around closed windows
- Black, perished sealant on frames
- Damp patches on the reveal after heavy rain
- Hard, cracked sealant around windows
If you let a flat or house near Stevenage station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Before you book anyone
- How long the guarantee is
- What happens if the job turns out different
- How the colour is chosen
- Who turns up on the day
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly.
Landlord and commercial work in Stevenage
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we will give you a quote.
What we do, step by step
We keep the work tidy and contained to the area we are working on, so you can carry on as normal. The job generally takes anything from an hour or two to a full day, depending on how many frames there are, and we tell you how long to leave it before we go. Jobs in a place the size of Stevenage range from town-centre flats to offices and family homes. Whichever it is, tell us how to get in, where to park and where the work is.
- Each frame is looked over and we agree which ones need resealing.
- We remove the old mastic and clean the frame edge and wall.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
Getting ready for the visit
- Where the joints are inside, avoid wetting them before we arrive
- For business premises, tell us about site rules or sign-in
- Move anything stored near the joints
Get a quote
Getting a quote is simple: let us know the job and the location, and roughly how big it is. A few pictures by email make the job easier to understand, and we will come back to you with a quote.
Advice
Places near Stevenage
Also in Stevenage
Stevenage questions
Can you help a landlord with a rental near Stevenage 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 will give you a fixed price before work begins.
Is it worth replacing old sealant in an older home in Stevenage?
If it hasn’t been replaced for some years, it’s generally worth it. Sealant doesn’t last for ever, and its life depends on use, cleaning and weather, and many homes in Stevenage may already be on their second or third set.
Should I try DIY first?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. If it does not work out, we can redo it.
Where are you based?
We work from Crawley. Our applicators cover Stevenage.
How many windows can you do in a day?
A few frames take a few hours. You’ll get a timescale with the quote.
Are you insured?
Yes. We’re fully insured.
Will the old sealant be removed?
Yes. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
Will resealing my frames help with draughts?
In many cases. The gap between frame and wall is a common source of draughts, and resealing inside and out closes it.