Kent · England
Sand mastic for sash & case windows in St Margarets, Kent
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in St Margarets and across Kent. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Modern sealant on a period surround
- Cement or filler used on old window joints that has cracked
- Failed mastic on an exposed elevation
How the visit works
Good joint work is mostly preparation, and we don’t rush it. Every joint is cleaned and dried before new material goes in. In total, it normally takes a few hours for a single window, longer for several. For a village or hamlet like St Margarets, the journey is planned in advance: let us know about lanes, gates and parking. 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.
- Old, loose mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Getting ready for the visit
- Tell us about any water getting in
- Mention any parking rules near the property
- Tell us about access, such as stairs, a lift or high-level joints
Ask for a quote
For a quick quote, get us on the phone, or email us if that is easier. Tell us about the joints that need doing and we will talk you through the work.
Advice
How we handle sand mastic in St Margarets
On many period windows, sand mastic looks right and suits the building. Newer frames generally get a flexible sealant instead, and we will talk through which suits your home. We are often asked to deal with open joints round the window box and a silicone bead on a sash window that spoils the look, across stone surrounds, sash and case windows and period & listed homes.
In a village or hamlet like St Margarets, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
All our work comes with a 12-month guarantee.
- Place
- St Margarets (DA4)
- Region
- Kent
- Guarantee
- One year on every job
- Price
- A clear price before we start
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Should I try it myself first?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
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.
What affects the cost of sand mastic
There’s no set price list, because jobs vary so much. The quote depends on:
- Any mould that needs treating
- How much old sealant there is and how hard it is to remove
- Access and height
- The size of the job
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. You’ll know the price before we begin.
Asking for a quote
When you call or email, it’s useful to know:
- Any access issues, like height or stairs
- Whether it’s a home or a business
- Where the job is, and your postcode
- A few pictures by email, if you can
Asking for a quote is easy: let us know what needs doing and where and its rough size. Photos by email help us understand the job, and we will take it from there.
What the job involves on each surface
Period and listed homes
Sand mastic is the like-for-like choice for many period homes. On listed buildings, check with your planning authority first.
Brick reveals
An open joint at a brick reveal lets weather in. Renewing the mastic closes it.
St Margarets: your questions answered
Will you come out to St Margarets?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Do you cover St Margarets for sand mastic?
Yes, St Margarets is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or email us with a few details of the job, and we’ll give you a clear price.
Do you work for landlords and businesses?
Yes, often. We can quote for several properties at once, and between tenancies is a good time for the work.
Do you offer different sealant colours?
Generally, yes. Sealants come in white, clear, grey and other colours, and we will agree it with you first.
What sealant do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We will tell you what we are using and why.
Do you work for hotels and businesses?
Yes. Hotels, offices and other businesses use us.
Is consent needed for window work on a listed home?
Check with your local planning authority. They decide whether consent is needed for work to your windows.
What do you need from me for a quote?
Only a few details: where it is, what you’ve noticed and how we reach it. Then call 0345 464 0079 or send us an email.
Frames and glazing around St Margarets
Historic houses like Lullingstone Castle (about 4.5 miles south-west) are a reminder that the area around St Margarets has older buildings as well as new. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For landlords with property near Farningham Road station, older sash windows in a rental need their mastic kept sound to keep the weather out. If you live in an older home near Church of St Margaret of Antioch, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
St Margarets is about 3 miles south-east of Dartford, in Kent. Wherever you are in the DA4 postcode area, our applicators can take on sand mastic. Our area takes in 922 places across Kent, large and small. There’s also a page for London, roughly 16 miles from St Margarets.
Our applicators cover all of DA4 for sand mastic. If you are just outside St Margarets, we cover South Darenth (1 mile south-west), Darenth (1 mile north), Green Street Green (1 mile east), Sutton at Hone (1 mile west) and Grubb Street (1 mile east). We also work in nearby towns such as Maidstone (15 miles south-east), Dartford (3 miles north-west), Sevenoaks (9 miles south), Gravesend (5 miles east), Tonbridge (15 miles south) and Northfleet (4 miles north-east).
Near you in St Margarets
We work in homes and buildings around Darenth Country Park, Leigh Academy and Fox & Hounds pub. The closest station to St Margarets is Farningham Road station, roughly 1.1 miles south-west of the centre. A little further out are Stone Museum of Geology (2.5 miles north) and Darent Valley Hospital (1.7 miles north). For a walk, there’s Sawyers Lake and Wansunt Pit.
What happens if it’s left?
Draughts round a sash window are not always the sashes. Open mastic joints round the box can let air in, and renewing the mastic closes them. Where a wall is exposed, as many are in small places like St Margarets, 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, plus any working-time requirements on site. Call for a quick quote and we will go through it with you.
Why St Margarets clients choose us
- Old sealant always removed completely
- Sanitary silicone with an anti-fungal additive in wet areas
- Every job guaranteed for a year
- 4.9 on Google from 180+ five-star reviews
Take a look at what affects the cost and our reviews.
Signs you need sand mastic in St Margarets
Water gets into small cracks in the mastic and loosens it further. Windows facing the weather tend to go first.
Keep an eye out for these signs:
- Cement or filler used on old window joints that has cracked
- Mastic worn away on windows facing the weather
- Mastic round period door frames that has failed
- Tired mastic found when preparing windows for paint
Schools such as Greenlands Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s.
Before you book anyone
- What product goes in the joint
- What insurance they hold
- Who does the work, and how experienced they are
- Which colour the sealant will be
When something else is needed
In fairness, some problems need a different trade:
- Sash cords, weights and draught-proofing of the sashes
- Cracked or broken glass
- Whether work needs listed building consent
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think.
Where we work in St Margarets
- Brick reveals
- Period & listed homes
- Stone surrounds
- Sash and case windows
- Timber door frames
- Tenement windows