Southampton · England
Sand mastic for sash & case windows in St Mary's, Southampton
Window and door surrounds in St Mary's need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Crumbling sand mastic round a window
- Cracked mastic round a front door frame
- Patchy fillers round a sash window
How the job changes by surface
Sash and case windows
Most of our sand mastic work is on sash windows. We renew the mastic round each box.
Timber door frames
Round a period front door, sand mastic gives the right look.
Sand mastic for homes and businesses in St Mary's
We renew sand mastic around sash windows and doors set in stone or brick. The old mastic is raked out, and new mastic is applied and shaped by hand. We work on stone surrounds, sash and case windows and period & listed homes, and common reasons people get in touch are failed mastic on an exposed elevation and old sand mastic that has cracked, crumbled or fallen out.
Around St Mary's, conservatories, garden rooms and patio doors are often part of the house. Their glazing joints and frame seals are as much a part of the job as the windows.
The work is covered for a year after we finish. If there’s a problem with it, please call 0345 464 0079 or send us an email.
- Place
- St Mary's (SO14, SO15, SO18)
- Region
- Southampton
- Guarantee
- A year, on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Windows and doors in St Mary's
St Mary's is close to the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. Both are hard on the mastic around older windows and doors, which can dry out and crack sooner where a building faces the weather. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
In the older streets around St Mary's Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Letting a property close to Southampton Central station? Then older sash windows in a rental need their mastic kept sound to keep the weather out. If you look after a building such as Hope Community School Southampton, its window and door frames need their mastic kept sound, just like a home’s.
St Mary's is about 1 mile south of Southampton, in Southampton. St Mary's gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. We cover 40 towns and villages across Southampton.
Jobs for sand mastic in SO14, SO15 and SO18 works the same way as everywhere else we cover. Streets in the area include New Road, Ogle Road and Marsh Lane, and we cover them all. Other places close to St Mary's include Northam (1 mile north-east), Inner Avenue (1 mile north), Peartree Green (1 mile east), Southampton (1 mile north) and Bitterne Manor (1 mile north-east). We also work in nearby towns such as Chartwell Green (3 miles north-east), Harefield (3 miles east), Maybush (3 miles north-west), Coxford (3 miles north-west), Lordswood (3 miles north-west) and Eling (4 miles west).
Local landmarks in St Mary's
Typical jobs here are in homes near The Joiners pub, Woolston School and Houndwell Park and the streets around them. St Mary's’s nearest station is Southampton Central station, about 0.8 miles west of the centre. A little further out are Netley Castle (2.5 miles south-east) and Bargate Guildhall Museum (under half a mile south-west). Open spaces near St Mary's include Netley Common.
Looking after it afterwards
Good habits help new joints last longer. A few tips:
- Have rotten timber repaired before new mastic goes in
- Sort the mastic before the decorators arrive
- Leave the new mastic unpainted
- Inspect the joints round the windows every year or so
Leave the new mastic alone while it firms up. It skins over quickly, but takes longer to harden fully.
Small cracks are a sign the mastic is ageing. It’s easier to renew it before it drops out.
Landlords, agents and businesses in St Mary's
We also work for property managers and facilities teams in St Mary's and across Southampton. Several sites can be quoted together.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Towns and villages near St Mary's
What else we do in St Mary's
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
A DIY attempt does not rule out a professional job. We cut it out and start again, so tell us about it when you ask for a quote.
How we quote for sand mastic
We don’t publish a price list. The quote depends on:
- The number of rooms or windows
- Mould in or behind the old joints
- How much old sealant there is and how hard it is to remove
- Which sealant suits the joint
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
Helping us quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- The type of property
- Any previous sealing or DIY work
- Any access issues, like height or stairs
- Pictures of the joints, sent by email
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.
Your questions about sand mastic in St Mary's
Do you work for landlords with property near Southampton Central station?
Yes, rental work is part of what we do. Just phone 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
Do you cover smaller places like St Mary's?
Yes. St Mary's is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Can you seal over the old sealant?
No. Fresh sealant does not stick to old sealant, and anything trapped underneath, including mould and water, stays there. It all has to come out first.
What is sand mastic?
It’s sand mixed with a linseed-oil-based binder, used between timber frames and stone or brick.
Can I choose the sealant colour?
In most cases you can choose. We’ll explain which colours are available.
Can old silicone round a sash window be swapped for sand mastic?
Yes. The silicone is cut out and the joint cleaned before the sand mastic goes in.
What do you put in the joint?
Each joint gets the product that suits it. Movement, water and weather all affect the choice, and we will tell you what we’re using.
Should I try DIY first?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs.
What sealant work can’t fix
A few problems are outside what sealant work can do:
- Decayed frames that need repair
- Broken panes
- Masonry that needs repairing
Not sure which it is? You can phone 0345 464 0079 or email us and we will tell you honestly before booking.
What we seal
- Sash and case windows
- Tenement windows
- Stone surrounds
- Timber door frames
- Brick reveals
- Period & listed homes
The process
Every visit runs the same way: we check the joints, protect the area around them, carry out the job and tidy away. It generally takes anything from a few hours to a full day, depending on how many windows. For a job in St Mary's, we agree the time, the access and parking before the day. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We check each window surround and the condition of the joint.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
How to prepare
- Keep children and pets away from the work area
- Tell us about access, such as stairs, a lift or high-level joints
- Mention if the joints have been sealed before
Get a quote
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job, and we’ll come back to you with a quote.