Hampshire · England
Sand Mastic in Knowle
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Knowle and across Hampshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Draughty sash windows at the surround
- A silicone bead on a sash window that spoils the look
- Tired mastic found when preparing windows for paint
How we handle sand mastic in Knowle
Fresh sand mastic forms a skin quite soon, but it takes longer to harden fully. Traditionally, sand mastic is left unpainted, so ask us before you decorate. We work on stone surrounds, timber door frames and period & listed homes, and the jobs we see most are mastic worn away on windows facing the weather and crumbling sand mastic round a window.
In a village or hamlet like Knowle, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
We stand behind the work with a 12-month guarantee.
- Where
- Knowle (PO17)
- Region
- Hampshire
- Guarantee
- 12 months on all our work
- Quote
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How the job changes by surface
Sash and case windows
On a sash window, the mastic joint shows on the outside, so a neat, even finish matters.
Period and listed homes
On a listed home or in a conservation area, the right material matters. Sand mastic is often the preferred finish.
Windows and doors in Knowle
Compared with the north and west, the South East gets less rain, 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 Church of St Francis, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. If you look after a building such as Orchard Lea Infant School, larger buildings have plenty of frames, and the mastic around each one ages.
Knowle is about 2 miles north of Fareham, in Hampshire. From the centre of Knowle to the outskirts, we cover sand mastic for every kind of property. Knowle is one of 683 places in Hampshire we cover. You can also see our page for Portsmouth, roughly 7 miles from Knowle.
Jobs for sand mastic in PO17 works the same way as everywhere else we cover. Sand mastic is available to properties on Serotine Close, Boundary Walk and Park Approach and the roads around them. Nearby, we also carry out sand mastic in Funtley (1 mile south), Tapnage (1 mile north-west), Heathfield (2 miles south), Segensworth (2 miles west) and Titchfield Park (2 miles south-west). Within a short drive, we also cover Winchester (13 miles north), Gosport (6 miles south-east), Havant (10 miles east), Eastleigh (9 miles north-west), Horndean (9 miles east) and Totton (13 miles west).
Landmarks near Knowle
We work in homes and buildings around The Miners Arms and The Henry Cort Community College and the streets around them. For rail, the closest station is Fareham station, roughly 2 miles south. Other landmarks nearby include Portchester Castle (4.9 miles south-east) and Knowle Hospital (less than half a mile north-east). Open spaces near Knowle include Portsdown Hill and Swanwick Lakes.
What else we do in Knowle
Quotes for sand mastic in Knowle
There’s no set price list. What we look at:
- How easy the joints are to reach
- Any working-time requirements on site
- How many rooms, windows or areas are involved
- The type of sealant required
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you are unsure, phone 0345 464 0079 or send us an email for an honest opinion and a quote.
Helping us quote
To make quoting easier, please include:
- Photos by email, if that’s easy
- Where the property is
- The type of property
- Access, such as stairs, a lift or height
For a quote, ring 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You’ll have a clear quote before any work starts.
Honest limits
We will always be straight with you, so here’s what new sealant won’t do:
- Decayed frames that need repair
- Broken panes
- Planning or listed building consent (your local planning authority decides)
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer before booking.
What we seal
- Brick reveals
- Tenement windows
- Stone surrounds
- Timber door frames
- Period & listed homes
- Sash and case windows
Leave it or put it right?
Not every draught comes from the sashes themselves. Open mastic joints round the box can let air in, and renewing the mastic closes them. Older cottages and farmhouses around Knowle can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
Combining jobs into one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
What you get with us
- 180+ five-star Google reviews
- Neat joints and a tidy finish
- Quality sealants from Arbo and Everbuild
- Experience in homes, commercial sites and hotels
See what affects the cost and what customers say.
Should I try it myself first?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
FAQs for Knowle
Can you do sand mastic in Knowle?
Yes, Knowle is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job.
Can you help a landlord with a rental near Fareham station?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Do you remove the old sealant?
Always. Sealing over old sealant is the main reason resealing fails early, so we never do it.
Do you have insurance?
Yes. Full insurance covers our work.
Do you guarantee sand mastic work?
There’s a 12-month guarantee on every job.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that normally means someone at home.
Can you replace silicone on a period window with sand mastic?
In most cases. We remove the silicone and clean the joint before the sand mastic goes in.
Can you seal over the old sealant?
No. The old sealant always comes out first, so the new joint bonds to clean surfaces.
How the visit works
Our applicators work methodically: protect, prepare, seal, tidy. Typically it takes anything from a few hours to a full day, depending on how many windows and we leave things clean and tidy. Somewhere like Knowle needs a little journey planning: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- First, we look at the surrounds with you and agree what needs doing.
- We rake out the old mastic and clean the joint.
- Large voids are packed out first, so the mastic isn’t too thick.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
Getting ready for the visit
- Try not to wet indoor joints just before the visit
- Move anything stored near the joints
- On commercial sites, let us know about site rules
Get a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email photos if that’s easy.
Advice
Do you need sand mastic in Knowle?
Water gets into small cracks in the mastic and pushes it out. Windows facing the weather tend to go first.
Keep an eye out for any of the following:
- Mastic round period door frames that has failed
- Patchy fillers round a sash window
- Open joints round the window box
- Crumbling sand mastic round a window
For landlords with property near Fareham station, any sash windows need sound mastic to keep draughts and rain out.
Questions to ask before you book
- Are they insured?
- Whether the sealant suits the joint
- What the quote includes, VAT included or not
- How the surfaces are prepared before sealing