Hampshire · England
Sand mastic for sash & case windows in Haslar, Hampshire
Problem with your window and door surrounds in Haslar? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- A silicone bead on a sash window that spoils the look
- Mastic worn away on windows facing the weather
- Gaps between timber frames and stone or brick
Work for landlords, hotels and businesses
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
About our sand mastic in Haslar
Burnt sand mastic is a traditional material that sits naturally against stone and brick. It’s a good fit for period properties, where modern sealant can look out of place. If you are dealing with cement or filler used on old window joints that has cracked and open joints round the window box, we can put it right.
Somewhere as small as Haslar, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
All of our work is guaranteed for twelve months, in Haslar and everywhere else we cover.
- Location
- Haslar (PO12)
- Region
- Hampshire
- Cover
- A year, on every job
- Quotes
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Why deal with it now?
Cement-based fillers and modern sealants do not always suit a period surround. Sand mastic matches what was there and that can be important for listed homes. Where a wall is exposed, as many are in small places like Haslar, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we will explain what it covers.
Why us?
- 180+ five-star Google reviews
- Any old sealant cut out fully, not covered over
- Arbo and Everbuild products
- More than 20 years in sealant work
Take a look at our cost guide or our reviews.
When something else is needed
Some problems need a builder, plumber or other trade rather than us:
- Whether work needs listed building consent
- Sashes that need overhauling
- Putty and glazing repairs
Not sure which it is? You can call 0345 464 0079 or send us an email and we will tell you honestly before you book.
Joints and surfaces we work on
- Timber door frames
- Tenement windows
- Sash and case windows
- Stone surrounds
- Brick reveals
- Period & listed homes
Signs you need sand mastic in Haslar
Age is the main cause. Even well-laid mastic needs renewing in time and how long it lasts depends on the weather it faces.
People usually contact us after spotting something like this:
- Window mastic to renew ahead of painting
- Silicone on a period window that looks wrong
- Cracked mastic round a front door frame
- Gaps where the frame meets the masonry
For landlords with property near Portsmouth Harbour station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
What your quote should include
- Are they insured?
- What the cure time is
- What guarantee comes with the work
- Whether all the old sealant comes out first
Windows and doors in Haslar
Haslar is within about 1 mile of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. Both are hard on the mastic around older windows and doors, which can dry out and crack sooner where a building faces the weather. London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For site and facilities teams at buildings such as Haselworth Primary School, the mastic around its windows and doors needs looking after like any other building’s. Homes close to St Francis include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Haslar is about 2 miles south-east of Gosport, in Hampshire. Anywhere in PO12, we can carry out sand mastic at your property. Across Hampshire, we cover 683 places, Haslar among them.
Work in PO12 is quoted and booked the same way as anywhere else. If you need sand mastic at a property on Froude Road, Military Road and Monckton Road or anywhere close by, we can help. Nearby, we also carry out sand mastic in Clayhall (1 mile north-west), Alverstoke (1 mile west), Portsmouth Point (1 mile north-east), Privett (2 miles north-west) and Portsea (2 miles north-east). Larger places within reach include Havant (8 miles north-east), Fareham (6 miles north-west), Horndean (10 miles north-east), Hedge End (12 miles north-west), Waterlooville (8 miles north-east) and Purbrook (7 miles north-east).
What’s near Haslar
Locally, jobs take us to homes and businesses close to The Fighting Cocks pub, Bay House School and St Vincent College. The nearest railway station is Portsmouth Harbour station, about 1.5 miles north-east of the centre. Nearby you will also find Tricorn Centre (2.3 miles north-east) and Southsea Castle (1.8 miles east). Not far away are West of the River Alver.
How it works
Most of a good job is in the preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it generally takes anything from a few hours to a full day, depending on how many windows. Somewhere like Haslar 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 look at the surrounds with you and agree the joints to renew.
- Old mastic and any loose material are raked out.
- We pack any deep voids first.
- We apply the mastic by hand and shape it.
- We dress the finish so it sits neatly against the masonry.
Before we arrive
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us if parking is tricky
- Keep children and pets away from the work area
Getting a quote
Getting a quote is simple: let us know the job and the location, and roughly how big it is. A few pictures by email make the job easier to understand, and we will take it from there.
Related advice
Places near Haslar
Also in Haslar
How to look after the new joints
How long the joints last depends on use and care. We suggest:
- Sort the mastic before the decorators arrive
- Clear gutters so water does not pour onto the windows
- Keep modern sealant off the mastic
- Do not paint over the new mastic
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
Sound mastic protects the frame. Failed mastic lets water reach the timber, which can lead to rot.
DIY sealant or a professional job?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
FAQs for Haslar
Can you help a landlord with a rental near Portsmouth Harbour station?
Yes. We work for landlords and letting agents as well as householders, and several properties can go on one quote. You can call 0345 464 0079 or send us an email with the details for a clear quote.
Will you come out to Haslar?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do the sealants smell?
There can be a smell while the sealant cures, but it fades. Opening a window helps.
Can I add another job to the visit?
Yes. Tell us about everything you’d like done.
Do you remove the old sealant?
Yes, always, and completely. New sealant will not bond properly to old, so any old material comes out before anything new goes in.
What does sand mastic cost?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote.
Can new sealant go over the old?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. It all has to come out first.
Which products do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We’ll tell you what we’re using and why.