Surrey · England
Window & door mastic in St John's, Surrey
Window mastic across St John's and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Untidy mastic left by window fitters
- Mastic that has split away from the wall
- Whistling draughts around closed windows
When something else is needed
In fairness, there are a few things sealant won’t fix:
- A sash or casement that will not close properly
- A failed sealed unit that has misted up
- A frame that has rotted at the joint
Not sure which it is? You can ring 0345 464 0079 or send us an email and we will tell you honestly.
What we seal
- Composite doors
- Window sills
- Timber windows & doors
- Aluminium frames
- uPVC windows
- Patio & French doors
Window mastic in St John's
Frames and walls do not move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. So the sealant has to stretch and recover, which is why we use a low-modulus product. We’re often asked to deal with untidy mastic left by window fitters and cracked sealant at the sill ends, across patio & French doors, uPVC windows and window sills.
Around St John's, conservatories, garden rooms and patio doors are often part of the house. Those joints need the same attention as the main windows, and any older timber or sash windows need a sealant that suits them.
Every job comes with our 12-month guarantee.
- Where
- St John's (GU21, GU22)
- Wider area
- Surrey
- Guarantee
- A year, on every job
- Quote
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Common problems we fix in St John's
Every frame moves through the day. A plastic or aluminium frame lengthens in sunshine and shortens as it cools, while the brick or render around it hardly moves. A sealant that can’t keep up eventually tears.
The most common problems we see are:
- Damp patches on the reveal after heavy rain
- Gaps where the sill meets the wall
- Untidy mastic left by window fitters
- Cracked or shrunken mastic around the frame
For site and facilities teams at buildings such as The Winston Churchill School A Specialist Sports College, the mastic around its windows and doors needs looking after like any other building’s.
Questions to ask before you book
- Whether all the old sealant comes out first
- Whether they’re fully insured
- Whether the sealant suits the joint
- What the quote includes, VAT included or not
For landlords and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we’ll give you a quote.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance.
What happens if it’s left?
If you’re painting or rendering, reseal at the same time. A clean new bead makes new paint or render look finished, and it’s easier while the walls are being worked on anyway. In an older home around St John's, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
The cost depends on the amount of work, how much old material has to come out and how easy the joints are to reach. We give a clear quote before we start.
Why us?
- Rated 4.9 stars on Google
- We agree the colour with you first
- Experience in homes, commercial sites and hotels
- Tidy, careful work
Read what affects the cost or what customers say.
What window mastic looks like in St John's
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Letting a property close to Woking station? Then sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. Homes close to St John's Church include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
St John's is about 1 mile west of Woking, in Surrey. If you need window mastic in St John's, it’s easy to get a quote: please ring 0345 464 0079 or drop us an email. We cover Surrey from our Crawley base, St John's included. St John's is one of 395 places in Surrey we cover for window mastic. We also work in Reading, around 19 miles away.
Here we cover the GU21 and GU22 postcode area for window mastic. If you need window mastic at a property on Pond Road, Copse Road and Raglan Road or anywhere close by, we can help. St John's sits on or near the A324. Close by, we work in Goldsworth Park (1 mile north-east), Woking (1 mile east), Westfield (2 miles south-east), Horsell (2 miles north-east) and Mimbridge (2 miles north). Within a short drive, we also cover Guildford (5 miles south), Camberley (6 miles west), Epsom (14 miles east), Farnham (11 miles south-west), Ewell (15 miles east) and Egham (8 miles north).
Near you in St John's
Typical jobs here are in homes near Hoe Valley School, The Oaktree School and Royal Oak pub. The nearest railway station is Woking station, about 1.6 miles east. Nearby you’ll also find Brookwood Hospital (1 mile west) and The Peacocks (1.6 miles east). Not far away are Brookwood Lye.
Your questions about window mastic in St John's
Is St John's within the area you cover?
Yes, we do. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Do you work for landlords with property near Woking station?
Yes, rental work is part of what we do. You can phone 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before we start.
Is it OK to seal over old sealant?
No, because it fails. The old sealant always comes out first, so the new joint bonds to clean surfaces.
Can you work on commercial sites?
Yes. We’ve worked for hotels, offices and other businesses and we’re fully insured.
Does someone need to be in?
If the work is inside, we need someone to let us in. Once we’ve agreed the job, you do not need to watch us work.
Will it make a mess?
We keep the work tidy. We protect what’s around the joints.
Do you work on first-floor windows?
Yes, as long as they can be reached safely. Tell us about access when you get in touch and we’ll plan for it.
Can you do several jobs on one visit?
Yes. Just list everything you need and we will quote it together.
Aftercare tips
Once the sealant has cured, a few habits help it last:
- Check the mastic once a year
- Keep paint off silicone joints
- Use gentle cleaners on frames and sealant
- Wipe condensation off the frames
Most silicone sealants will not take paint, so mention any painting plans before work begins. There are paintable sealants for joints that need it.
Water trapped behind a failed joint can start rot in timber frames and sills. Rotten timber needs a joiner, not a sealant, so it pays to reseal before that happens.
Different surfaces, different methods
Aluminium frames
Coated aluminium needs a compatible sealant. We use a neutral-cure product.
uPVC windows
Fitters’ mastic on plastic frames is sometimes thin and rushed. It comes out, deep gaps get backing rod and the joint is resealed.
Places near St John's
Also in St John's
What happens on the day
The work is kept neat and contained to the area we are working on, so you can get on with your day. The job usually 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. For a job in St John's, we agree the time, the access and parking before the day. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- We check how each frame can be reached safely.
- Old, cracked mastic is removed completely, along with any loose debris.
- The surfaces are cleaned and left dry.
- Deep voids are backed, then the sealant is gunned in.
- We tool the joint so water runs off, then clear up.
Before we arrive
- Mention any leaks or damp you’ve noticed
- Tell us about any previous sealing or DIY attempts
- Let us know about parking restrictions
How to get a quote
If you’re in St John's and need window mastic, call 0345 464 0079 or email us. Tell us what the problem is and where, and we’ll agree the price before any work begins.