Kent · England
Window & door mastic in Hartley, Kent
Window mastic across Hartley and nearby, with old sealant always removed completely.
- Hard, cracked sealant around windows
- Old mastic that has gone black or come away
- Leaking joints at the ends of sills
How we handle window mastic in Hartley
Frames and walls do not move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. That is why the joint needs a flexible, low-modulus sealant rather than something rigid. We work on aluminium frames, timber windows & doors and composite doors, and the jobs we see most are old mastic that has gone black or come away and cracked sealant at the sill ends.
In smaller places like Hartley, homes range from older cottages to newer houses, with windows to match: timber, uPVC and aluminium. The right sealant depends on the frame and on what it sits in.
Your job is guaranteed for a year, as with all our work.
- Place
- Hartley (DA3)
- Region
- Kent
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Landlords, agents and businesses in Hartley
Housing providers, facilities teams and property managers book us too in Hartley and across Kent. Several sites can be quoted together.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
Why it’s worth doing now in Hartley
Choosing the product is half the job. Interior caulk and bathroom silicone are not made for exterior frame joints. An exterior, low-modulus sealant stays flexible in sun and frost. Around Hartley, water from a failed joint in an older home can soak into timber and plaster, and that is a much bigger job than renewing the sealant.
Combining jobs into one visit is generally more efficient than separate visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
Why choose Mr Mastic in Hartley
- Old sealant always removed completely
- Full insurance on every job
- Sanitary silicone with an anti-fungal additive in wet areas
- 180+ five-star Google reviews
Towns and villages near Hartley
More services for Hartley
The process
When we arrive, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before any work begins. The work generally takes a morning for a couple of windows and a door. For a job in Hartley, we agree the time, the access and parking before the day. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We check each frame and agree which ones need doing.
- The old mastic is cut out and the surfaces cleaned back.
- We fit backing rod in deep gaps so the sealant is the right depth.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- Finally we tidy up and check each joint.
Preparing for the visit
- Clear items away from the joints we’re working on
- Mention any sign-in or site rules at work premises
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
Every job is quoted individually, so start by telling us what you need. Simply ring 0345 464 0079 or send us an email and describe the job.
Related advice
When to call us in Hartley
Sun, frost and rain wear sealant out. Sunlight dries the surface out, and over the years it loses its give, cracks and comes away.
These are the problems we are asked about most:
- Old mastic that has gone black or come away
- Rushed sealant from a window installation
- Leaking joints at the ends of sills
- Sealant in the wrong colour for the frame
For site and facilities teams at buildings such as Hartley Primary Academy, its window and door frames need their mastic kept sound, just like a home’s.
Comparing quotes
- What insurance they hold
- The length of the guarantee
- What the quote includes, VAT included or not
- Who turns up on the day
Honest limits
It helps to know what we can’t do too:
- A failed sealed unit that has misted up
- A frame that has rotted at the joint
- Faulty window hardware
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we will tell you honestly.
What we seal
- Patio & French doors
- uPVC windows
- Timber windows & doors
- Window sills
- Composite doors
- Aluminium frames
Questions from Hartley
Is Hartley in your area for window mastic?
Yes. We work across London and the South East, and Hartley is part of that. Just phone 0345 464 0079 or email us with a few details of the job, and we will give you a clear quote.
Is Hartley within the area you cover?
Yes, smaller places are covered as well as towns. We work across London and the South East. Just mention lanes, gates or anything else about the route when you book.
How long will my window job take?
A few frames take a few hours, while a whole house takes longer. We confirm the timing with your quote.
How long before the joint can be used?
Cure times vary by product. Before we leave, we will tell you the cure time.
I rent my home. Can I book you?
Yes. Ask your landlord first, and we can send them the quote if that helps.
Do I have to be there?
That depends on where the joints are. Inside work needs someone to give us access, while outside work can sometimes be arranged differently.
Does the work come with a guarantee?
Yes. Our 12-month guarantee covers every job, inside or out.
What do you need from me for a quote?
Where the job is, what the problem is and roughly how big it is. Photos by email help too.
Different surfaces, different methods
Timber windows & doors
Older timber windows in stone or brick can suit sand mastic rather than modern sealant. We can talk through the options.
Composite doors
Front doors take the weather head on. Those corners get the most care.
Windows and doors in Hartley
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. Historic houses like Cobham College (about 3.9 miles east) are a reminder that the area around Hartley has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
If you live in an older home near Church of Saint Mary, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. For landlords with property near Longfield station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Hartley is about 4 miles south-west of Northfleet, in Kent. Across the DA3 area, we cover window mastic for homes and businesses. Our Kent coverage runs to 922 places, Hartley among them. You can also see our page for London, about 19 miles away.
All of DA3 is covered for window mastic. If you need window mastic at a property on Church Road, Dickens Close and Stack Lane or a nearby road, we can help. If you’re just outside Hartley, we cover Longfield (1 mile north), New Barn (1 mile north-east), Longfield Hill (1 mile east), New Ash Green (1 mile south) and Nash Street (2 miles east). We also work in nearby towns such as Maidstone (13 miles south-east), Dartford (5 miles north-west), Sevenoaks (9 miles south-west), Gravesend (4 miles north-east), Tonbridge (13 miles south) and Northfleet (4 miles north-east).
What’s near Hartley
Around Hartley, our work takes us to homes and buildings near Railway Tavern, Rectory Meadow and Longfield Academy, among other places. Hartley’s nearest station is Longfield station, about 0.8 miles north-west of the centre. Other landmarks nearby include Darent Valley Hospital (4 miles north-west) and Stone Castle (4.1 miles north). Not far away are Sawyers Lake.
Looking after it afterwards
After the cure time, these simple habits help:
- Wash the frames with mild soapy water
- Ventilate rooms so frames do not stay wet inside
- Check the mastic once a year
- Clear any debris from frame drain holes
Keep sill grooves and drainage slots clear, so water can run away instead of sitting against the joint.
Draughts get worse, not better. As the old mastic shrinks further, more air gets through, and heat escapes around the frame. A new joint closes it up.