Southampton · England
Sand Mastic in Northam
Specialist sand mastic for Northam: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Tired mastic found when preparing windows for paint
- Open joints round the window box
- Weathered mastic on the most exposed windows
Sand mastic in Northam
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s made from sand and a linseed-oil-based binder, applied by hand. On period homes, it looks right where silicone wouldn’t. We work on brick reveals, sash and case windows and stone surrounds, and the jobs we see most are wind and rain getting in round a sash window and silicone on a period window that looks wrong.
Homes around Northam range from older properties to newer houses, and their windows range just as widely. Each frame material needs the right sealant against the right wall.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Where
- Northam (SO14, SO19, SO18)
- Wider area
- Southampton
- Guarantee
- 12 months on all our work
- Quote
- A clear price before we start
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Landlords, agents and businesses in Northam
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.
If you manage several properties in or around Northam, jobs at different addresses can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
Towns and villages near Northam
What else we do in Northam
How we quote for sand mastic
The price is agreed before any work begins. It takes into account:
- Any mould that needs treating
- How easy the joints are to reach
- How much old sealant there is and how hard it is to remove
- How many areas need sealing
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you’re not sure whether it needs doing, phone 0345 464 0079 or email us for an honest opinion and a quote.
Asking for a quote
When you call or email, it’s useful to know:
- The rough size of the job
- If it’s domestic, commercial or a hotel
- Whether it has been sealed before
- How we’d reach the joints
Want a quote for sand mastic? Please phone 0345 464 0079 or send us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.
What sand mastic looks like in Northam
Northam 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. With historic houses such as Southampton Tudor House and Garden (about 1.3 miles south-west) nearby, there’s older building stock in the area around Northam as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
If you live in an older home near Church of St Augustine, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. Letting a property close to Bitterne station? Then any sash windows need sound mastic to keep draughts and rain out.
Northam is about 1 mile south-east of Southampton, in Southampton. Homes, rented property, offices and hotels in Northam is covered for sand mastic, old or new, large or small. Every job comes with our 12-month guarantee. Northam is one of 40 places in Southampton we cover for sand mastic.
We cover every part of the SO14, SO19 and SO18 postcode area for sand mastic and the streets around it. Streets in the area include Sea Road, Lumpy Lane and Cross Road, and we cover them all. Close by, we work in Peartree Green (1 mile south), Bitterne Manor (1 mile north), Itchen (1 mile south-east), St Mary's (1 mile south-west) and Bitterne (1 mile east). Within a short drive, we also cover Regents Park (3 miles west), Maybush (3 miles north-west), Coxford (3 miles north-west), Lordswood (3 miles north-west), Eling (5 miles west) and Rownhams (4 miles north-west).
Around Northam
Typical jobs here are in homes near Inspire Enterprise Academy, East Park and The Engineers Arms, among other places. The nearest railway station is Bitterne station, roughly 0.6 miles north. Well-known places in the area include Bitterne Local History Society Heritage And Research Centre (0.8 miles east) and Marlands Shopping Centre (1.2 miles west). The countryside around Northam includes Netley Common.
Do you need sand mastic in Northam?
Paint, silicone or cement used over old mastic causes problems. They don’t suit the joint and we normally remove them.
It’s worth asking for a quote if you see:
- Gaps where the frame meets the masonry
- Cement or filler used on old window joints that has cracked
- Wind and rain getting in round a sash window
- Old sand mastic that has cracked, crumbled or fallen out
Schools such as Bitterne Manor Primary School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
What your quote should include
- Whether they’re fully insured
- What guarantee comes with the work
- Who turns up on the day
- What the cure time is
How the visit works
The work is kept neat and contained to the joints we’re treating, so you can carry on as normal. The job normally takes a few hours for a single window, longer for several, and we tell you how long to leave it before we go. A visit to Northam 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.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic isn’t too thick.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
How to prepare
- Let us know about parking restrictions
- Mention any leaks or damp you’ve noticed
- Mention any sign-in or site rules at work premises
Getting a quote
For sand mastic in Northam, ring 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and you will get a clear quote before work begins.
Read more
Northam questions
I let a flat near Bitterne station. Can you help?
Yes. We work for landlords and letting agents as well as homeowners. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we’ll give you a clear quote.
Will you come out to Northam?
Yes. Northam 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 replace silicone on a period window with sand mastic?
Yes. We remove the silicone and clean the joint, then point it with sand mastic.
Will there be a smell?
Some sealants have a smell while they cure, but it fades. Ventilation helps.
Is the work guaranteed?
Our one-year guarantee covers every job, sand mastic included.
What is sand mastic?
Sand plus a binder based on linseed oil. It’s built up in the joint by hand and finished to sit neatly against the masonry.
Can I choose the sealant colour?
Yes. Sealants come in white, clear, grey and other colours for many products, and we will agree it with you first.
Is consent needed for window work on a listed home?
Checking first is sensible. Ask your local planning authority whether consent is needed for listed or conservation-area properties.
Leave it or put it right?
An open joint round the frame lets weather in. Left, water can reach the timber and the wall so renewing it early protects the window. Homes in smaller places like Northam can face more weather, and failed outside joints let damp into walls. Inside, a split seal lets water into floors and panels just as it would anywhere.
The cost reflects the work involved, not a rough estimate. That is why we ask a few questions first.
Why choose Mr Mastic in Northam
- 180+ five-star Google reviews
- Homes, businesses and hotels
- An ARBOMaster approved applicator
- Anti-fungal silicone where joints get wet
Read what affects the cost or customer reviews.
Looking after it afterwards
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Do not paint over the new mastic
- Sort the mastic before the decorators arrive
- Make sure water runs off the sill
- Find out about consent before window work on a listed home
Make sure water drains away from the window surround. Water sitting against the mastic shortens its life.
Crumbling mastic lets rain into the joint. It can soak into the frame and the surrounding masonry so early renewal protects both.
Honest limits
We will not take on work that will not last, so here’s what sealant cannot put right:
- Decayed frames that need repair
- Damaged stone surrounds
- Decisions on consent for listed homes
If you’re not sure, just call 0345 464 0079 or email us and we will give you a straight answer.
Joints and surfaces we work on
- Period & listed homes
- Sash and case windows
- Stone surrounds
- Brick reveals
- Tenement windows
- Timber door frames