Hertfordshire · England
Window Mastic in Broad Colney
Mastic around window and door frames, sills and patio doors for householders, landlords and businesses in Broad Colney. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Rain getting in at the frame or under the sill
- Mastic that has split away from the wall
- A bead that does not match the frame
Window mastic in Broad Colney, done properly
The new joint doesn’t have to be white. White, brown, anthracite grey, black and clear sealants are all available, so the line suits the frame instead of standing out. If you have leaking joints at the ends of sills and sealant in the wrong colour for the frame, we can put it right, on window sills, timber windows & doors and patio & French doors alike.
Around Broad Colney, 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.
A one-year guarantee comes as standard, so you’re not left on your own once the job is done.
- Place
- Broad Colney (AL2)
- Wider area
- Hertfordshire
- Cover
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Can I do it myself?
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.
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
Leave it or put it right?
Redecorating is a good moment to renew the mastic. A clean new bead makes new paint or render look finished, and it’s easier while the walls are being worked on anyway. Around Broad Colney, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote and we will talk you through it.
Why us?
- Sealant colour chosen to suit
- More than 20 years in sealant work
- Neat joints and a tidy finish
- Any old sealant cut out fully, not covered over
See what affects the cost or our reviews.
Different surfaces, different methods
Timber windows & doors
On period timber windows, traditional sand mastic is sometimes the better choice. We will tell you which suits your home.
Patio & French doors
Heavy door frames can move more than windows. A flexible sealant copes with that.
Broad Colney: your questions answered
Is Broad Colney within the area you cover?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
I let a flat near Park Street station. Can you help?
Yes. We work for landlords and letting agents as well as homeowners, and several properties can go on one quote. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we will give you a clear quote.
Do I need to be at home?
That depends on where the joints are. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
Is the work guaranteed?
Yes. All our work carries a 12-month guarantee, and we are fully insured.
Can new sealant go over the old?
No. New silicone will not bond to old silicone, and anything trapped underneath, including mould and water, stays there. We remove it all first.
Do you have sealant for grey or black windows?
Yes. Grey and black frames get grey or black sealant, and wood-effect frames generally suit brown.
Can new window sealant be painted?
It depends on the sealant. Silicone is not paintable, but some hybrid sealants are. Mention any painting plans before we start.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator, and we are fully insured.
Landlord and commercial work in Broad Colney
Letting agents often deal with us directly. Tell us the address, the job and how access works.
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
Frames and glazing around Broad Colney
Historic houses like High Elms Manor (about 4.1 miles west) are a reminder that the area around Broad Colney 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. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Rented homes near Park Street station change hands often, and sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. For site and facilities teams at buildings such as Saint Bernadette Catholic Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Broad Colney is about 3 miles south-east of St Albans, in Hertfordshire. Every kind of property in Broad Colney can book us for window mastic, old or new, large or small. Every job comes with our one-year guarantee. Across Hertfordshire, we cover 381 places, Broad Colney among them. You can also see our page for London, about 17 miles away.
Every address in AL2 is within our area for window mastic, from the main roads to the quietest streets. Other places close to Broad Colney include London Colney (1 mile north), Shenleybury (1 mile south-east), Tyttenhanger (2 miles north), Sleapshyde (3 miles north-east) and Colney Heath (3 miles north-east). We also work in nearby towns such as Watford (6 miles south-west), Hemel Hempstead (7 miles west), Stevenage (14 miles north), St Albans (3 miles north-west), Welwyn Garden City (7 miles north-east) and Harpenden (7 miles north).
What’s near Broad Colney
We work in homes and buildings around The White Lion pub and Samuel Ryder Academy and the streets around them. Broad Colney’s nearest station is Park Street station, about 1.9 miles north-west. Other landmarks nearby include Hilfield Castle (4.5 miles south) and Radlett and District Museum (2.5 miles south). Not far away are Verulamium Lake and Broad Colney Lakes.
Do you need window mastic in Broad Colney?
Plenty of failed mastic was poorly applied in the first place. Mastic laid onto dusty, damp or crumbling surfaces never bonded as it should, so it comes away long before its time.
Common reasons people contact us are:
- Black, perished sealant on frames
- Rushed sealant from a window installation
- Damp patches on the reveal after heavy rain
- Draughty joints inside around the window
In the older streets around Church of St Peter, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Questions to ask before you book
- How the joint is cleaned and prepared
- Whether VAT is included
- Whether they’re fully insured
- How much experience the applicator has
When it is not the sealant
Some problems need a builder, plumber or other trade rather than us:
- Rotten timber, which needs a joiner first
- Draughts through the window seals rather than the frame
- Damp problems in the wall away from the window
If in doubt, phone 0345 464 0079 or email us and we’ll say what we think before booking.
Where we work in Broad Colney
- Window sills
- uPVC windows
- Aluminium frames
- Patio & French doors
- Timber windows & doors
- Composite doors
What happens on the day
Once we’re on site, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. Most jobs then take a morning for a couple of windows and a door. In a small place like Broad Colney, access is usually the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- Each frame is looked over and we agree which ones need resealing.
- The old mastic is cut out and scraped back to clean surfaces.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- On commercial sites, let us know about site rules
- Clear the area around the work
- Let us know if you’ve seen damp or leaks
How to get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, ring 0345 464 0079 or drop us an email.