Greater London · England
Custom House Window Mastic
We cover Custom House for mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly.
- Black, perished sealant on frames
- Draughty joints inside around the window
- Hard, cracked sealant around windows
Window mastic for homes and businesses in Custom House
There are two joints on most windows. Outside, the mastic keeps rain out; the internal joint closes the gap to the plaster and stops draughts. We seal one or both, depending on what’s needed. We work on composite doors, patio & French doors and aluminium frames, and the jobs we see most are mastic that’s falling out in pieces and hard, cracked sealant around windows.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Custom House.
A one-year guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Custom House (E16, E13)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Custom House questions
Do you cover Custom House for window mastic?
Yes, Custom House is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job.
Can parking be tricky for a visit in Custom House?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot.
Can you quote for more than one area?
Yes. Just list everything you need.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator, which is run for the Arbo sealant brand.
Where are you based?
We’re based in Crawley, and we work across South East England, London and Scotland.
What sealant do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference.
Can I do it myself?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Do you have sealant for grey or black windows?
Yes. White, brown, anthracite grey, black and clear sealants are all available, so the joint suits the frame.
Why it’s worth doing now in Custom House
Draughts and leaks don’t always mean new windows. If the frames and glass are in good order, resealing the joints is often all that is needed. If we find failed glass units or worn seals, we will tell you. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble for homes in Custom House.
Some things make a job bigger or smaller: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Why Custom House customers choose us
- Fully insured
- Neat joints and a tidy finish
- We agree the colour with you first
- A sealant colour to suit the surroundings
Landlords, agents and businesses in Custom House
Hotels need rooms back in use, so we plan the work room by room. We’ve worked in hotels as well as homes and businesses.
Landlords and letting agents in Custom House can book us as well as homeowners. Sealant work between tenants is a simple way to keep a property in good order.
Looking after it afterwards
Aftercare is simple, and it makes a real difference:
- Don’t paint over the silicone
- Keep drainage slots and sill grooves clear
- Wash the frames with mild soapy water
- Repaint timber before it’s bare
A yearly look round the frames is enough. Cracks and lifting edges are easy to spot early.
Water gets in quietly when mastic fails. You might not see it until plaster blows or a damp patch appears inside. Catching it early keeps the fix to a reseal.
Do you need window mastic in Custom House?
Frames are never completely still. A plastic or aluminium frame lengthens in sunshine and shortens as it cools, while the brick or render around it hardly moves. A sealant that cannot keep up eventually tears.
Look out for these signs:
- Sealant in the wrong colour for the frame
- Mastic that’s falling out in pieces
- Gaps where the sill meets the wall
- Water coming in at the bottom corners of a door
As a London address, Custom House can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- Are they insured?
- Whether you can choose the colour
- How the joint is cleaned and prepared
- Whether all the old sealant comes out first
Surface by surface
Window sills
Every drop off the glass ends up on the sill, so the sill ends and the joint under the frame are vital. Each is cleaned out and resealed.
Patio & French doors
Patio and French doors have the longest joints on most houses. Most leaks start at the bottom corners, so they get particular care.
What happens on the day
Most of a good job is in the preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it normally takes a few hours for a handful of frames, longer for a whole house. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Custom House. A visitor permit or a nearby bay makes the visit run more smoothly.
- We check each frame and agree which ones need doing.
- The old mastic is cut out and the surfaces cleaned back.
- Deep gaps are filled with backing rod to set the depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Finally we tidy up and check each joint.
Getting ready for the visit
- Let us know about parking restrictions
- Try not to wet indoor joints just before the visit
- Let us know about earlier repairs to the joints
Ask for a quote
We do not publish a price list. Instead, your job gets its own clear quote. To arrange one, phone 0345 464 0079 or drop us an email.
Read more
Custom House homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. 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.
Homes close to St Matthew's Church include some older properties, and the joint between an old wall and a newer frame is generally the first place rain gets in. Schools such as St Joachim's Catholic Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s.
Custom House is about 1 mile south of Canning Town, in Greater London. Custom House gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Custom House is one of 764 places in Greater London we cover.
Every address in E16 and E13 is within our area for window mastic. Whether your property is on Tree Road, Ethel Road and Booth Road or a nearby road, we can help. Custom House sits on or near the A1020. Other places close to Custom House include West Silvertown (1 mile south-west), Silvertown (1 mile south), Canning Town (1 mile north), Royal Docks (1 mile east) and Limmo Peninsula (1 mile west). Within a short drive, we also cover London (5 miles west), City of Westminster (8 miles west), Marylebone (8 miles west), Kensington (10 miles west), St Pancras (6 miles west) and Shoreditch (5 miles west).
Around Custom House
Typical jobs here are in homes near Thames Barrier Park, The Royal Docks Community School and Royal Docks Academy, among other places. Custom House has its own railway station: Custom House station. Well-known places in the area include Gallions Reach Shopping Park (2.2 miles east) and Charlton Athletic Museum (1.5 miles south). For a walk, there’s Gilbert's Pit and Tower Hill.
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.