Windsor and Maidenhead · England
Sand mastic for sash & case windows in Cookham Dean, Windsor and Maidenhead
We cover Cookham Dean for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly and a 12-month guarantee.
- Crumbling sand mastic round a window
- Weathered mastic on the most exposed windows
- Cement or filler used on old window joints that has cracked
Sand mastic for homes and businesses in Cookham Dean
Across Cookham Dean, we renew sand mastic around sash and case windows. Each joint is raked out, prepared and pointed by hand, finished to suit the masonry. Typical jobs include wind and rain getting in round a sash window and failed mastic on an exposed elevation, on brick reveals, stone surrounds and sash and case windows.
Mastic can only go onto a dry, clean joint, so window work in Cookham Dean is booked around the forecast. Tell us about access to every side of the house, including upper-floor windows.
There’s a 12-month guarantee on every job.
- Place
- Cookham Dean (SL6)
- Region
- Windsor and Maidenhead
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Why act early in Cookham Dean
Gaps round a sash window let in rain and draughts. Left, water can reach the timber and the wall so renewing it early protects the window. Around Cookham Dean, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
No two jobs are quite the same, so each one gets its own quote. The number of joints, how easy they are to reach and the sealant needed all play a part, and we’ll explain the quote if you ask.
Why choose Mr Mastic in Cookham Dean
- Rated 4.9 stars on Google
- Homes, businesses and hotels
- We leave the area clean and tidy
- 20+ years of sealant experience
Read how sealant jobs are priced and customer reviews.
Cookham Dean: your questions answered
Do you cover smaller places like Cookham Dean?
Yes, smaller places are covered as well as towns. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do you work for landlords with property near Cookham station?
Yes, we work for letting agents and landlords. Just call 0345 464 0079 or drop us an email and tell us about the property, and we will send you a clear quote.
What is sand mastic?
It’s sand mixed with a linseed-oil-based binder for the joint between timber frames and masonry.
How long will you be here?
Typically it takes anything from a few hours to a full day, depending on how many windows. Larger jobs naturally take longer, and we will say how long yours will take.
How long does sand mastic take to go off?
Not straight away. The skin forms first, and the full set comes later, and we’ll tell you what to expect.
Do I need to be at home?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
Is it possible to paint over sand mastic?
Sand mastic is normally left unpainted, as guidance on traditional windows advises. Ask us before decorating.
Should I use sand mastic or silicone?
Sand mastic generally suits period timber windows best. Modern frames normally suit a flexible sealant.
When to call us in Cookham Dean
Decorating can disturb tired mastic. Many people find it crumbling when they prepare the windows.
People generally contact us after spotting something like this:
- Draughts and rain around sash boxes
- Tired mastic found when preparing windows for paint
- Old cement repairs round a window that have failed
- Failed mastic on an exposed elevation
For site and facilities teams at buildings such as Cookham Dean CofE Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Before you book anyone
- How long to leave it before use
- How the colour is chosen
- What the quote includes, VAT included or not
- Which sealant they’ll use, and why
What affects the quote in Cookham Dean
Your quote is based on your job. We look at:
- How many areas need sealing
- Mould in or behind the old joints
- Any working-time requirements on site
- Access and height
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What we need to know
There’s no need for technical detail. It helps if you can tell us:
- Roughly how big the job is
- Access, such as stairs, a lift or height
- The problem you’ve noticed
- Where the job is, and your postcode
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is. When it suits you, phone 0345 464 0079 or drop us an email.
When something else is needed
It helps to know what we cannot do:
- Sashes that need overhauling
- Decayed frames that need repair
- Crumbling stone or brickwork round the window
If you’re not sure, just call 0345 464 0079 or send us an email and we will give you a straight answer before booking.
What we seal
- Stone surrounds
- Timber door frames
- Brick reveals
- Period & listed homes
- Tenement windows
- Sash and case windows
Landlords, agents and businesses in Cookham Dean
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will quote.
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Also near Cookham Dean
What else we do in Cookham Dean
Cookham Dean homes and 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. Historic houses like Cliveden (about 2.5 miles east) are a reminder that the area around Cookham Dean has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
For landlords with property near Cookham station, any sash windows need sound mastic to keep draughts and rain out. If you live in an older home near Church of St John the Baptist, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Cookham Dean is about 2 miles south-east of Marlow, in Windsor and Maidenhead. Across the SL6 area, we cover sand mastic for homes and businesses. 57 places in Windsor and Maidenhead are on our list, large and small. Reading is on our list too, around 12 miles away.
Our applicators cover all of SL6 for sand mastic. If you need sand mastic at a property on Kings Lane, Popes Lane and Hills Lane or a nearby road, our applicators can take on the job. Other places close to Cookham Dean include Cookham (1 mile east), Bisham (1 mile west), Furze Platt (2 miles south), Marlow (2 miles north-west) and Temple (2 miles west). Further out, we also cover Maidenhead (3 miles south), Windsor (7 miles south-east), Boyn Hill (3 miles south), North Ascot (10 miles south), Dedworth (7 miles south-east) and Broomhall (12 miles south-east).
What’s near Cookham Dean
We work in homes and buildings around Jolly Farmer pub and Furze Platt Senior School, among other places. Cookham Dean’s nearest station is Cookham station, roughly 1 mile east of the centre. Well-known places in the area include Marlow Community Hospital (1.6 miles north-west) and Marlow Museum (1.5 miles north-west). Green spaces nearby include Taplow Lake and Carpenter's Wood.
Different surfaces, different methods
Timber door frames
Round a period front door, sand mastic gives the right look.
Stone surrounds
We take care not to mark the stone while raking out the old mastic.
How it works
A visit follows a simple pattern: we look at the joints together, protect the area around them, do the work and clear up. Most jobs take a few hours per window, depending on the condition of the joints. Somewhere like Cookham Dean needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- We check the window surrounds and agree which joints need renewing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The finish is dressed so it sits neatly against the stone or brick.
Before we arrive
- Tell us about any water getting in
- Let us know about earlier repairs to the joints
- Plan for the work area to be out of bounds to pets and children
Getting a quote
We quote each job on its own, so start by telling us what you need. Simply ring 0345 464 0079 or send us an email and describe the job, and photos are welcome.