Hampshire · England
St Cross Window Mastic
Mastic around window and door frames, sills and patio doors for homes and businesses in St Cross and across Hampshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Hard, cracked sealant around windows
- Gaps between the frame and the inside reveal
- Gaps left after new windows were fitted
Window mastic in St Cross
Behind a thin line of old mastic there’s sometimes a deep void. Packing it solid with sealant gives a joint that can’t flex, so deep gaps get backing rod first. That way the new bead bonds to the frame and the wall only. If you’re dealing with cracked internal joints between frame and plaster and mastic that’s falling out in pieces, we can help.
In a smaller place like St Cross, some walls face open ground and catch the full force of the weather, so exposed windows and doors face the weather head on. That is hard on the mastic around frames and sills.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we will sort it.
- Location
- St Cross (SO22, SO23)
- Wider area
- Hampshire
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Questions from St Cross
I let a flat near Winchester station. Can you help?
Yes. We work for letting agents and landlords as well as householders, and several properties can be quoted together. Just ring 0345 464 0079 or email us with the address and what needs doing, and we will send you a clear quote.
Will you come out to St Cross?
Yes, St Cross is covered. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
What information do you need?
Just the basics: the address or postcode, what’s wrong and any access issues. After that, simply ring 0345 464 0079 or email us.
Can I add another job to the visit?
Yes. Just list everything you need and you will get one quote.
Where is Mr Mastic based?
Our base is in Crawley, and we work across South East England, London and Scotland.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages.
Can you seal the gap between the frame and the plaster indoors?
Yes. The outside joint keeps the weather out, and the inside joint stops draughts and finishes the reveal. We do one or both.
Is it messy?
We keep the work tidy. We protect what’s around the joints.
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. A few tips:
- Paint up to the joint, not over it
- Avoid blasting the frames with a pressure washer
- Repaint timber before it’s bare
- Wash the frames with mild soapy water
A yearly look round the frames is enough. Cracks and lifting edges are easy to spot early.
Water trapped behind a failed joint can start rot in timber frames and sills. Once wood has rotted, it needs repair before it can be sealed, so early resealing is worth it.
Surface by surface
Aluminium frames
Aluminium moves with heat, and the frames are often slimmer than uPVC. A neat, narrow bead in a colour to match suits the frame.
Timber windows & doors
Timber moves with moisture as well as heat, so a flexible sealant is essential. The paint or stain needs to be sound where the sealant meets it.
Towns and villages near St Cross
What else we do in St Cross
Why it’s worth doing now in St Cross
Working on frames from a ladder with a sealant gun isn’t easy, especially on upper floors. We cut out properly, back deep gaps and tool every joint neatly, in a sealant suited to the wall. Around St Cross, 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.
What you pay reflects the work, not guesswork. That’s why we ask a few questions first and agree the price before starting.
Why choose Mr Mastic in St Cross
- We agree the colour with you first
- Anti-fungal silicone where joints get wet
- Domestic, commercial and hotel work
- White, clear, grey or another colour, product permitting
Take a look at our cost guide or what customers say.
Honest limits
Some problems need a builder, plumber or other trade rather than us:
- Rotten timber, which needs a joiner first
- A sash or casement that won’t close properly
- Worn gaskets, brush seals or a door that has dropped
If you are not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
Joints and surfaces we work on
- Window sills
- Aluminium frames
- Patio & French doors
- uPVC windows
- Composite doors
- Timber windows & doors
Should I try it myself first?
If you’ve already had a go yourself, that is fine. We cut it out and start again.
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
Frames and glazing around St Cross
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.
Rented homes near Winchester station change hands often, and renewing tired window mastic between tenants heads off draught and damp complaints. If you look after a building such as St Faith's Church of England Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
St Cross is about 1 mile south of Winchester, in Hampshire. Our applicators cover window mastic for homes and businesses in St Cross and the surrounding area. St Cross is one of 683 towns and villages in Hampshire we cover. We also work in Southampton, about 10 miles from St Cross.
Our applicators cover all of SO22 and SO23 for window mastic. Local streets include Edgar Road, Hubert Road and Grange Road, all of which we cover. We also cover Badger Farm (1 mile west), Stanmore (1 mile north-west), Winchester (1 mile north), Bar End (1 mile east) and Highcliffe (1 mile north-east). Larger places within reach include Eastleigh (6 miles south), Fareham (15 miles south), Andover (13 miles north-west), Totton (12 miles south-west), Chandler's Ford (5 miles south-west) and Hedge End (9 miles south).
Local landmarks in St Cross
We work in homes and buildings around St. Cross Park, The Bell Inn Public House and Kings' School, among other places. The nearest railway station is Winchester station, about 1.3 miles north. A little further out are The Gurkha Museum (0.6 miles north-east) and Royal Hampshire County Hospital (0.9 miles north). Green spaces nearby include Hockley Meadows and Twyford Down.
Do you need window mastic in St Cross?
Sills take more water than any other part of a window, and the ends of the sill, where it meets the wall, are where it gets in. Failed sealant there lets rain into the wall or behind the frame.
Keep an eye out for any of the following:
- Gaps where the sill meets the wall
- Cold air getting in at the frame edge
- Water coming in at the bottom corners of a door
- Gaps left after new windows were fitted
In the older streets around St. Cross Church, the joint between an old wall and a newer frame is normally the first place rain gets in.
What your quote should include
- Which colour the sealant will be
- What preparation is included
- Are they insured?
- How long to leave it before use
The process
There is not much for you to do on the day. Point us to the joints and we’ll get on with it. The work itself takes a few hours for a few frames, or a day or more for a whole house from start to finish. A visit to St Cross is planned like any other: the time, the access and where to park are agreed in advance. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- First, we go round the frames with you and agree the list.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- Move anything stored near the joints
- Let us know if you’ve seen damp or leaks
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
If you are in St Cross and need window mastic, phone 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and we will agree the price before any work begins.