Hampshire · England
Thedden Window Mastic
Window and door frames in Thedden need attention? We remove the old material, prepare the joints and seal them properly.
- Black, perished sealant on frames
- Draughty joints inside around the window
- Rain getting in at the frame or under the sill
Window mastic for homes and businesses in Thedden
Homes in Thedden have every kind of window: 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. If you are dealing with old mastic that has gone black or come away and untidy mastic left by window fitters, we can help, on window sills, uPVC windows and aluminium frames alike.
Homes in small places like Thedden often stand in the open, with little to shelter their windows from wind and rain. That exposure dries out and cracks the mastic around frames and sills faster.
Each job carries a 12-month guarantee, whatever its size.
- Where
- Thedden (GU34)
- Wider area
- Hampshire
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
DIY sealant or a professional job?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
When to call us in Thedden
Plenty of failed mastic was poorly applied in the first place. Sealant run over dust, wet brick or loose mortar didn’t grip properly, and it lets go sooner than it should.
Look out for these signs:
- A bead that doesn’t match the frame
- Rushed sealant from a window installation
- Cracked internal joints between frame and plaster
- Leaking joints at the ends of sills
Managing a site like Amery Hill School? Then larger buildings have plenty of frames, and the mastic around each one ages.
Comparing quotes
- What the quote includes, VAT included or not
- When the joint can take water or movement
- How much experience the applicator has
- The length of the guarantee
Why act early in Thedden
Getting a straight, even bead on an outside frame takes practice, especially upstairs. We cut out properly, back deep gaps and tool every joint neatly, using a product chosen for the frame and wall. Older cottages and farmhouses around Thedden can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
Instead of a standard rate, we price the job in front of us: how many joints, what’s in them now and how we reach them. You will know the price before we begin.
Why choose Mr Mastic in Thedden
- A 12-month guarantee on all work
- Colour agreed with you before we start
- White, clear, grey or another colour, product permitting
- Rated 4.9 stars on Google
Read what affects the cost and what customers say.
How to look after the new joints
To keep the joints looking good and working properly:
- Do not aim a pressure washer at the joints
- Wipe condensation off the frames
- Keep paint and stain on wooden frames in good order
- Make sure the drainage slots are not blocked
Wipe the frames with soapy water when you clean the windows, and keep solvents and harsh chemicals off the joint.
Look out for the warning signs: split or missing mastic, gaps, damp patches inside or black mould on the reveal. Any of these is worth a call.
Other services in Thedden
Windows and doors in Thedden
Historic houses like Bentworth Hall (about 1 mile west) are a reminder that the area around Thedden has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. 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.
For an older house near a landmark such as St Peter's, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. If you let a flat or house near Alton station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Thedden is about 2 miles west of Alton, in Hampshire. If you need window mastic in Thedden, it’s easy to get a quote: please phone 0345 464 0079 or email us. We cover Hampshire from our Crawley base. Thedden is one of 683 towns and villages in Hampshire where we work for window mastic. Reading is on our list too, about 21 miles from Thedden.
Work in GU34 works the same way as everywhere else we cover. We also cover Beech (1 mile south-east), Wivelrod (1 mile south-west), Bentworth (1 mile north-west), Holt End (1 mile west) and New Copse (2 miles west). Within a short drive, we also cover Basingstoke (9 miles north), Winchester (14 miles south-west), Farnborough (15 miles north-east), Fleet (12 miles north-east), Aldershot (13 miles north-east) and Petersfield (10 miles south).
Landmarks near Thedden
The nearest railway station is Alton station, about 2.6 miles east. A little further out are Alton Community Hospital (1.6 miles east) and Barton Castle (3.9 miles west). The countryside around Thedden includes King's Hill.
Surface by surface
Window sills
Sills catch the water running down the glass, so the joints at each end and underneath matter. They’re cut out and resealed with exterior sealant.
Patio & French doors
Heavy door frames can move more than windows. The sealant must cope with it without cracking.
Thedden: your questions answered
I let a flat near Alton station. Can you help?
Yes, landlords and agents are among the people we work for. Just phone 0345 464 0079 or drop us an email with the address and what needs doing, and we will give you a clear quote.
Do you cover smaller places like Thedden?
Yes, we do. We work across London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
What do you need from me for a quote?
A short description and the location, with photos by email if possible. If we need more, we’ll ask.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses.
Do I need to be at home?
That depends on where the joints are. For work indoors, someone needs to let us in, while outside work can sometimes be arranged differently.
Can you do the inside joint as well?
Yes, we do both. Indoors, we seal between the frame and the plaster or reveal.
Can new sealant go over the old?
No. Fresh sealant doesn’t stick to old sealant, and it traps any mould or water underneath. It all has to come out first.
Can I add another job to the visit?
Yes. Tell us about everything you’d like done.
What happens on the day
Once we’re on site, we compare the joints with what we discussed. If we find something unexpected, we talk it through with you first. Most jobs then take a few hours for a handful of frames, longer for a whole house. Somewhere like Thedden needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- We check how each frame can be reached safely.
- All the failed sealant is cut away.
- The surfaces are cleaned and left dry.
- Backing rod fills deep voids and the sealant goes in on top.
- The joint is shaped to shed water and the area tidied.
How to prepare
- Let us know about parking restrictions
- Let us know if you’ve seen damp or leaks
- Plan for the work area to be out of bounds to pets and children
Get a quote
We don’t publish a price list. Instead, your job gets its own clear quote. To arrange one, call 0345 464 0079 or send us an email.
Read more
For landlords and businesses
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Hotels need rooms back in use, 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.