Wokingham · England
Sand mastic for sash & case windows in California, Wokingham
Sand mastic for California, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Draughts and rain around sash boxes
- Tired mastic found when preparing windows for paint
- Old cement repairs round a window that have failed
FAQs for California
Do you cover California for sand mastic?
Yes, California is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or email us with a few details of the job.
Can you help a landlord with a rental near Crowthorne station?
Yes. We work for letting agents and landlords as well as homeowners, and several properties can go on one quote. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Can new sealant go over the old?
No, because it fails. We remove every bit of old sealant first, so the new sealant bonds properly.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover California and the rest of Wokingham, along with the rest of our area.
Are you ARBOMaster approved?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
Can sand mastic be painted?
It’s traditionally left unpainted, as guidance on traditional windows advises. Talk to us before any painting near it.
What do you need from me for a quote?
Where the job is, what the problem is and roughly how big it is. If you can, email a few pictures.
Do you remove the old sealant?
Yes. All of the old material is cut out and the joint cleaned before resealing.
Sand mastic in California
Sand mastic skins over fairly quickly, but it takes longer to harden fully. Traditional guidance is not to paint over it, so ask us before you decorate. If you have cement or filler used on old window joints that has cracked and a silicone bead on a sash window that spoils the look, we can help, on brick reveals, tenement windows and stone surrounds alike.
Outdoor sealant needs dry, clean surfaces, so work on frames around California is planned for dry weather. Let us know about access to all the frames, upstairs ones included.
All of our work is guaranteed for twelve months, in California and everywhere else we cover.
- Place
- California (RG40)
- Wider area
- Wokingham
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Also near California
Other services in California
Windows and doors in California
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Rented homes near Crowthorne station change hands often, and any sash windows need sound mastic to keep draughts and rain out. Schools such as Gorse Ride Junior School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
California is about 3 miles south-west of Wokingham, in Wokingham. California gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. California is one of 35 places in Wokingham where we work for sand mastic. There’s also a page for Reading, roughly 7 miles from California.
All of RG40 is covered for sand mastic. Streets in the area include Warren Lane, White Horse Lane and Fernbank, and we cover them all. If you’re just outside California, we cover Arborfield Garrison (1 mile west), Finchampstead (1 mile south-east), Barkham (1 mile north), Langley Common (1 mile north-west) and Eversley (1 mile south-west). Further out, we also cover Reading (7 miles north-west), Wokingham (3 miles north-east), Woodley (5 miles north), Earley (5 miles north-west), Crowthorne (3 miles east) and Lower Earley (4 miles north-west).
Around California
We work in homes and buildings around The Queen's Oak pub, Bohunt School Wokingham and Shepperlands Farm Nature Reserve and the streets around them. For rail, the closest station is Crowthorne station, about 2.4 miles east of the centre. Other landmarks nearby include Beaumys Castle (4.7 miles west) and Wokingham Hospital (2.6 miles north-east). Not far away are Horseshoe Lake and Holt Copse & Joel Park.
How the visit works
When we arrive, we start by going over the job with you. Surfaces next to the work are protected before work begins. Most jobs take anything from a few hours to a full day, depending on how many windows. In a small place like California, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- First, we look at the surrounds with you and agree what needs doing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- 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
- For business premises, tell us about site rules or sign-in
- Mention if the joints have been sealed before
- Keep children and pets away from the work area
Ask for a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is. Whenever you’re ready, ring 0345 464 0079 or drop us an email.
Read more
Looking after it afterwards
Good habits help new joints last longer. A few tips:
- Renew mastic before redecorating the windows
- Get any rot dealt with first
- Ask us before painting near the mastic
- Find out about consent before window work on a listed home
Do not touch or press the mastic while it hardens. It forms a skin fairly soon but needs longer to fully harden.
Once mastic starts to crumble, rain gets in. That water can reach the timber frame and the wall, so renewing it early is worth it.
For landlords and businesses
Failed sealant is one of the commonest items on a check-out report, and it’s easy to sort out between tenants. Several properties can be quoted together.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
What affects the quote in California
Every job gets its own quote. These are the things that affect it:
- How much old sealant there is and how hard it is to remove
- Working hours on commercial sites
- Access and height
- The size of the job
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether we need extra access for height. Your quote takes all of that into account.
Asking for a quote
Photos help, but a description is a good start. Try to tell us:
- Any access issues, like height or stairs
- Pictures of the joints, sent by email
- The address or postcode of the job
- If someone has resealed it before
Every job is quoted individually. Just ring 0345 464 0079 or send us an email with the details.
When something else is needed
Before booking, it’s worth knowing the limits:
- Damaged stone surrounds
- Sashes that rattle, stick or will not open
- Rotten sashes, sills or window boxes (a joiner’s job)
If you’re not sure, just call 0345 464 0079 or send us an email and we will give you a straight answer.
Joints and surfaces we work on
- Brick reveals
- Sash and case windows
- Tenement windows
- Timber door frames
- Stone surrounds
- Period & listed homes
Signs you need sand mastic in California
Timber frames move with the seasons. The movement cracks the mastic little by little.
If you can see any of these, it’s time to have the joints looked at:
- Cement or filler used on old window joints that has cracked
- Crumbling sand mastic round a window
- Mastic worn away on windows facing the weather
- Window mastic to renew ahead of painting
Homes close to Church of St James include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What your quote should include
- Whether they’re fully insured
- How much experience the applicator has
- How the joint is cleaned and prepared
- Whether VAT is included
How the job changes by surface
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair, so check who is responsible first.
Timber door frames
A neat sand mastic joint round a front door suits a period home.