Hertfordshire · England
Datchworth Glazing Silicone
Problem with your glazing joints in Datchworth? We remove the old material, prepare the joints and seal them properly, and the work is guaranteed for a year.
- Rooflight joints letting water in
- Water running down inside the glass
- Glass-to-glass joints that have split
About our glazing silicone in Datchworth
Cracked, stained or lifting silicone on glass spoils the look and lets water in. It comes off cleanly, without marking the glass and reseal the joint. If you’re dealing with new silicone smeared over old sealant and water running down inside the glass, we can help.
Outdoor sealant needs dry, clean surfaces, so work on frames around Datchworth is planned for dry weather. Let us know about access to all the frames, upstairs ones included.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Location
- Datchworth (SG3)
- Wider area
- Hertfordshire
- Guarantee
- A year, on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Work for landlords, hotels and businesses
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we’ll quote.
In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. We’ve worked in hotels as well as homes and businesses.
Places near Datchworth
What else we do in Datchworth
Frames and glazing around Datchworth
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. Historic houses like Aston Bury (about 1.9 miles north) are a reminder that the area around Datchworth 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 is traditional sand mastic.
Letting a property close to Knebworth station? Then glazing joints are worth checking at the end of a tenancy, before a small leak grows. If you look after a building such as St Michael's Woolmer Green CofE VA Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Datchworth is about 4 miles north of Welwyn Garden City, in Hertfordshire. Anywhere in SG3, our applicators can take on glazing silicone. Datchworth is one of 381 places in Hertfordshire where we work. We also work in London, about 25 miles from Datchworth.
Postcode districts we cover here for glazing silicone: SG3. Streets in the area include Brookbridge Lane, Nutcroft and Meadow Close, and we cover them all. We also cover Bull's Green (1 mile south), Woolmer Green (1 mile west), Burnham Green (1 mile south), Hook's Cross (1 mile north-east) and Tewin Wood (1 mile south). We also work in nearby towns such as Hemel Hempstead (15 miles south-west), Stevenage (4 miles north), St Albans (10 miles south-west), Bishop's Stortford (14 miles east), Welwyn Garden City (4 miles south) and Harpenden (8 miles west).
Around Datchworth
Typical jobs here are in homes near The Tilbury pub. Datchworth’s nearest station is Knebworth station, about 1.6 miles north-west. Other landmarks nearby include Benington Castle (3.5 miles north-east) and Datchworth Museum (less than half a mile south). Open spaces near Datchworth include Mardley Heath.
Aftercare tips
Good habits help new joints last longer. Our tips:
- Stick to mild cleaners on glass
- Keep air moving in the conservatory
- Wipe the screen down after showering
- Do not use a blade near the sealant
Check the joints once a year. Spotting a crack early means a simpler fix.
Cracked glazing silicone means the joint has failed. Resealing now is a small job compared with fixing water damage later.
How it works
There isn’t much for you to do on the day. Show us the job and we’ll take it from there. The job generally takes a few hours for most jobs from start to finish. In a small place like Datchworth, access is usually the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First, we trace the leak and check it’s coming through a sealant joint.
- The old sealant is removed from the glass and frame without scratching them.
- Surfaces are cleaned with a solvent suited to glass and the frame.
- Glazing silicone suited to the joint is applied and tooled.
- We look over every joint and, where we can, test it with water.
Getting ready for the visit
- Keep pets and children clear of the area while we work
- Tell us about any previous sealing or DIY attempts
- Let us know about stairs, lifts or work at height
Ask for a quote
Need a quote? Please phone 0345 464 0079 or drop us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Read more
What happens if it’s left?
A new conservatory roof is a big job. If the leak is a failed sealant joint renewing the joint is the simpler fix. If the roof is the problem, we’ll say so. Around Datchworth, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
Leaving a failed joint generally makes the job bigger, not smaller, as water and mould keep getting in. If you are not sure whether it needs doing, call 0345 464 0079 or drop us an email for an honest opinion and a quote.
Why choose Mr Mastic in Datchworth
- White, clear, grey or another colour, product permitting
- Neat joints and a tidy finish
- A sealant colour to suit the surroundings
- Any old sealant cut out fully, not covered over
FAQs for Datchworth
Do you work for landlords with property near Knebworth station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear price.
Do you cover smaller places like Datchworth?
Yes, Datchworth is covered. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Can you reseal the base of a glass balustrade?
We can, if the base joint is sealed. Send us pictures and we’ll take a look when you phone 0345 464 0079 or drop us an email.
What sealant do you use on glazing?
A glazing silicone chosen for the joint. Neutral-cure products suit most glass and frames.
Do you replace glass?
No, our work is the silicone. A glazier replaces glass and units.
Where do you work from?
We are a Crawley-based firm, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Can you match the sealant colour?
Yes. Sealants come in white, clear, grey and other colours, and we agree the colour with you before work begins.
Is it worth trying it myself?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs.
DIY sealant or a professional job?
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.
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
What we’re called out for in Datchworth
Glass and frames expand and contract with the temperature, and they do not move by the same amount. In time, the sealant splits or pulls away.
These are the problems we are asked about most:
- Sealant that was laid over old silicone and failed
- Water escaping where a screen meets the wall
- Drips on the inside of a conservatory window
- Failed sealant around rooflight glass
If you live in an older home near Church of All Saints, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
What your quote should include
- Whether all the old sealant comes out first
- What guarantee comes with the work
- Whether they’re fully insured
- Whether VAT is included
What sealant work cannot fix
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Condensation trapped between two panes
- Cracked or broken glass
- Rotten or badly damaged frames
If you are not sure, just call 0345 464 0079 or email us and we will give you a straight answer before you book.
Joints and surfaces we work on
- Shower screens
- Conservatory frames
- Glass balustrade bases
- Rooflights
- Glass-to-glass joints
- Glass-to-frame joints