Hertfordshire · England
Knebworth Remedial Sealant
Removing failed, mouldy or leaking sealant and putting it right for homes and businesses in Knebworth and across Hertfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Over-sealed joints coming away
- Gaps opening along the back of the worktop
- Products that weren’t meant for the joint
Knebworth questions
Is Knebworth 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.
Do you work for landlords with property near Knebworth station?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before we start.
Will the old sealant be removed?
Yes. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
What happens if the problem is the tray or the plumbing?
You’ll hear it from us. If it’s a cracked tray, a failed valve or a leaking waste, resealing will not fix it, and we won’t reseal for the sake of it.
Can failed expansion joints be resealed?
Yes. Where mortar or filler has been used instead of sealant, it’s removed where it can be, then the joint is sealed properly.
Are you an approved applicator?
Yes. We hold ARBOMaster approved applicator status and we’re fully insured too.
When is the sealant fully cured?
It depends on the product. We tell you how long to leave it before we go.
How long will it take to strip and reseal the joint?
That depends on how many layers there are and how many joints. We will tell you before any work starts.
About our remedial sealant in Knebworth
Remedial jobs in Knebworth normally fall into a few patterns: sealant over sealant, mould under the bead, leaks that come back and movement joints that have split. We strip each one back and start from scratch. Typical jobs include a second bead peeling off the first and gaps opening along the back of the worktop, across botched or over-sealed joints, expansion joints and mouldy bath & shower sealant.
In a smaller place like Knebworth, homes are mostly houses and bungalows rather than flats, some older and some much newer. Sealant and grout wear out here just as they do in a big town.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we will put it right.
- Where
- Knebworth (SG3)
- Wider area
- Hertfordshire
- Guarantee
- A year, on every job
- Quotes
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What sealant work can’t fix
A few problems are outside what sealant work can do:
- Cracks in the fitting rather than the joint
- Old mastic in a building from before 2000 that should be checked for asbestos before it’s disturbed
- A bath, tray or worktop that moves until it’s properly fixed
If you’re not sure, just ring 0345 464 0079 or drop us an email and we’ll give you a straight answer.
What we seal
- Mouldy bath & shower sealant
- Failed movement joints
- Shrunken worktop sealant
- Leaking tray & enclosure joints
- Expansion joints
- Botched or over-sealed joints
Surface by surface
Leaking trays & enclosures
When failed joints are the cause, they’re all cut out and renewed, including the screen profile and tray edges.
Windows & doors
Smeared or badly matched mastic can be cut out and redone neatly, in a colour that suits the frame.
How the visit works
We work through the job in order: protect, prepare, seal, tidy. Typically it takes a few hours, depending on how many layers have to come out and we leave things clean and tidy. In a smaller place like Knebworth, parking is seldom the issue; lanes, gates and long drives are worth mentioning. If the job is outside, tell us about side access and how high the joints are.
- The failure is looked at first, so we know whether it’s sealant, movement or water from elsewhere.
- Old beads and residue are removed down to clean surfaces.
- Mould is treated and the joint dried.
- The right product goes in, with backing where the joint moves.
- The joint is tooled and you’re told about anything else we found.
How to prepare
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know about parking restrictions
- Keep pets and children clear of the area while we work
Getting a quote
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job, and we’ll take it from there.
Read more
Common problems we fix in Knebworth
Sealant needs a clean, dry surface with no grease on it. Residue, moisture or dust left in the joint weaken the bond, and the joint starts to come away early.
It’s worth asking for a quote if you see:
- Over-sealed joints coming away
- Smears and lumps from a botched reseal
- Decorators’ caulk around a bath or shower
- Dark patches showing through the sealant
In the older streets around Church of St Martin, older homes can move a little, which is hard on rigid grout and tired sealant.
Comparing quotes
- Whether VAT is included
- Are they insured?
- How the colour is chosen
- What guarantee comes with the work
Quotes for remedial sealant in Knebworth
Some jobs are bigger than they look, and some smaller. The main factors:
- How much there is to do
- When we can work, for business premises
- How easy the joints are to reach
- How much old sealant there is and how hard it is to remove
What it costs depends on the size of the job, how much old material has to come out and how easy the joints are to reach. We give a clear quote before we start, so you know where you stand.
Asking for a quote
Before you ask for a quote, have a think about:
- Any previous sealing or DIY work
- How we’d reach the joints
- The rough size of the job
- If it’s domestic, commercial or a hotel
We quote each job on its own. Just phone 0345 464 0079 or drop us an email with the details and send photos if you have them.
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Bathrooms and kitchens in Knebworth
Most of the South East has hard water, which leaves limescale on sealant, grout and fittings.
If you let a flat or house near Knebworth station, failed or mouldy sealant is worth putting right between tenancies, before it turns into a leak. If you look after a building such as Knebworth Primary and Nursery School, its toilets, changing areas and kitchens need their sealant renewed like any other building’s.
Knebworth is about 3 miles south of Stevenage, in Hertfordshire. We provide remedial sealant to homeowners, landlords and businesses in Knebworth and the surrounding area. Our Hertfordshire coverage runs to 381 places, Knebworth among them. For nearby work, see our London page.
Every address in SG3 is covered for remedial sealant, from the main roads to the quietest streets. Remedial sealant is available to properties on London Road, Deanscroft and Lytton Fields and the roads around them. If you are just outside Knebworth, we cover Woolmer Green (1 mile south), Bragbury End (1 mile north-east), Oaklands (2 miles south), Datchworth (2 miles south-east) and Shephall (2 miles north). Larger places within reach include Hemel Hempstead (14 miles south-west), Stevenage (3 miles north), St Albans (10 miles south-west), Bishop's Stortford (15 miles east), Welwyn Garden City (5 miles south) and Harpenden (8 miles south-west).
Around Knebworth
Locally, jobs take us to homes and businesses close to Barnwell School and Knebworth Park, among other places. There’s a railway station in Knebworth itself: Knebworth station. Other landmarks nearby include Benington Castle (3.6 miles north-east) and Datchworth Museum (1.7 miles south-east). Not far away are Mardley Heath.
Landlord and commercial work in Knebworth
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together, and we’re fully insured.
Hotels need rooms back in use, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.