Isle of Wight · England
Sand mastic for sash & case windows in Northwood, Isle of Wight
Sand mastic for Northwood and the surrounding area: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Cement or filler used on old window joints that has cracked
- Failed mastic on an exposed elevation
- Tired mastic found when preparing windows for paint
Aftercare tips
To keep the joints looking good and working properly:
- Go gently near the mastic when preparing windows
- Plan mastic work ahead of painting
- Keep modern sealant off the mastic
- Don’t paint over the new mastic
Keep gutters and sills clear so water runs away from the surround. Water sitting against the mastic shortens its life.
Good mastic helps keep the frame dry. Failed mastic lets water reach the timber and timber that stays wet can rot.
How we handle sand mastic in Northwood
Traditional burnt sand mastic that sits naturally against stone and brick. It’s a good fit for period properties, where modern sealant can look out of place. Common call-outs are for failed mastic on an exposed elevation and mastic round period door frames that has failed, across brick reveals, timber door frames and period & listed homes.
Around Northwood, many homes face open ground, so their windows and doors take the full weather. Exposed frames and sills lose their mastic sooner than sheltered ones.
We stand behind the work with a 12-month guarantee, so you are covered after we’ve gone.
- Location
- Northwood (PO31)
- Wider area
- Isle of Wight
- Guarantee
- 12 months on all our work
- Quotes
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why it’s worth doing now in Northwood
Not every draught comes from the sashes themselves. Gaps between the frame and the wall can be just as bad and new mastic seals them. Older cottages and farmhouses around Northwood can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
Instead of a standard rate, we look at what your job involves: the amount of work, the old material and the access. The price is agreed before we begin.
Why book with us
- Domestic, commercial and hotel work
- An ARBOMaster approved applicator
- 20+ years of sealant experience
- Old sealant always removed completely
Take a look at what affects the cost or what customers say.
Questions from Northwood
Is Northwood within the area you cover?
Yes, we do. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Can you do sand mastic in Northwood?
Yes, Northwood is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job, and we’ll give you a clear price.
How long will you be here?
Typically it takes a few hours for a single window, longer for several. Bigger jobs take longer, and we will say how long yours will take.
How long does sand mastic take to harden?
It takes a while. The skin forms first, and the full set comes later, and we will tell you what to expect.
What do you put in the joint?
Each joint gets the product that suits it. Movement, water and weather all affect the choice.
Is it possible to paint over sand mastic?
The usual advice is to leave sand mastic unpainted. If you’re redecorating the window, ask us first and we will talk you through it.
Is it worth trying it myself?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional.
Where do you work from?
Our base is Crawley, with over 20 years’ experience. We work across South East England, London and Scotland.
Different surfaces, different methods
Sash and case windows
The mastic round a sash window is on show so we finish it carefully.
Brick reveals
An open joint at a brick reveal lets weather in. Renewing the mastic closes it.
Landlords, agents and businesses in Northwood
We work for letting agents and landlords as well as householders. Sealant work between tenants is a simple way to keep a property in good order.
Letting agents often deal with us directly. Tell us the address, the job and how access works.
The process
Most of a good job is in the preparation, and we don’t rush it. Joints are cleaned back and dried before anything new goes in. In total, it normally takes anything from a few hours to a full day, depending on how many windows. For a village or hamlet like Northwood, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- Sand mastic is mixed and applied by hand, then shaped to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
Before we arrive
- On commercial sites, let us know about site rules
- Keep pets and children clear of the area while we work
- Tell us about any previous sealing or DIY attempts
Getting a quote
For a quote, call 0345 464 0079 or send us an email with the location and a short description of the problem. We will send you a clear quote before any work starts.
Advice
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 chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Sand mastic in Northwood: local notes
Northwood is within about 2 miles of 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. London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
In the older streets around All Saints' Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Northwood is about 1 mile south of Cowes, in the Isle of Wight. For sand mastic in and around Northwood, please ring 0345 464 0079 or email us for a quick quote. We cover the Isle of Wight from our Crawley base. 125 places in the Isle of Wight are on our list, from the larger towns to small villages. Our Portsmouth page covers work nearby (11 miles or so).
We cover every part of PO31 for sand mastic and the streets around it. Local streets include Nodes Road, Wyatts Lane and Uplands Road, and we cover them all. We also cover the places around Northwood: Rew Street (1 mile west), Gurnard (1 mile north), Cowes (1 mile north), Noke Common (2 miles south) and Parkhurst (2 miles south). Larger places within reach include Newport (3 miles south), Ryde (7 miles east), Sandown (9 miles south-east), Shanklin (10 miles south-east), Ventnor (11 miles south-east) and Oakfield (7 miles east). Island and remote addresses take a little more planning, so tell us where you are when you ask for a quote.
Near you in Northwood
Typical jobs here are in homes near Cowes Enterprise College and The Travellers Joy pub, among other places. Well-known places in the area include Isle of Wight Natural History Centre (0.5 miles north) and West Cowes Castle (1.7 miles north). Open spaces near Northwood include Mill Hill and Briddlesford Nature Reserve.
Places near Northwood
More services for Northwood
Do you need sand mastic in Northwood?
Over the years, sand mastic weathers. It hardens, cracks and starts to come away from the frame or the masonry.
The most common problems we see are:
- Silicone on a period window that looks wrong
- Cracked mastic round a front door frame
- Old sand mastic that has cracked, crumbled or fallen out
- Weathered mastic on the most exposed windows
Managing a site like Northwood Primary School? Then its window and door frames need their mastic kept sound, just like a home’s.
Comparing quotes
- Whether they’re fully insured
- Whether VAT is included
- Whether all the old sealant comes out first
- Whether the sealant suits the joint