Hertfordshire · England
Remedial Sealant in Blackmore End
We cover Blackmore End for removing failed, mouldy or leaking sealant and putting it right. Old material cut out, joints cleaned and sealed neatly and a one-year guarantee.
- Repeat leaks from the same joint
- Movement joints that have split or pulled away
- Gaps opening along the back of the worktop
How we quote for remedial sealant
We don’t publish a price list, because no two jobs are the same. What we look at:
- The number and length of the joints
- Mould in or behind the old joints
- The old material and how stubborn it is
- How easy the joints are to reach
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
What to tell us for a quote
What to tell us when you ask for a quote:
- Any access issues, like height or stairs
- The problem you’ve noticed
- Photos by email, if that is easy
- Where the job is, and your postcode
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and add photos by email if you can.
About our remedial sealant in Blackmore End
Removing failed sealant is the hardest part of the job. Every layer is cut out, the residue cleaned off and the joint degreased, without scratching tiles, trays or frames. Only then can new sealant bond. We work on failed movement joints, expansion joints and mouldy bath & shower sealant, and people most often call us about wide, uneven beads that look worse than the old ones and beads that never stuck properly.
In a village or hamlet like Blackmore End, homes are often older cottages and farmhouses alongside a few newer houses. Older walls and timber floors can move a little, and cracked grout and split sealant are often the first signs.
All our work comes with a one-year guarantee, wherever you are in Hertfordshire.
- Where
- Blackmore End (AL4)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Surface by surface
Over-sealed & botched joints
Botched joints sometimes have damaged edges from earlier scraping. We work carefully to avoid adding to it, and tell you about any damage we find.
Mouldy bath & shower sealant
Mould that has grown into silicone does not clean out for good. The sealant is cut out completely, the joint treated with a mould remover and dried before anti-fungal sanitary silicone goes in.
How to look after the new joints
Looking after new joints is easy:
- Deal with small splits early
- Report a tray that rocks or a worktop that lifts
- Keep bleach and abrasives off the bead
- Always have old sealant cut out, not covered
Give the new sealant its full cure time: follow the cure time we give you.
If a joint has failed more than once, stop resealing it. Get the cause found first, otherwise the next attempt will fail too.
The process
Once we are 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 few hours for a typical bath or shower, longer where several layers have been applied. Somewhere as small as Blackmore End, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We protect the surfaces around the joint.
- The botched or failed sealant is cut away completely.
- The joint is degreased and checked for movement and leaks.
- Once dry, a suitable sealant is applied and tooled.
- You get the cure time and our view on why the joint failed.
Preparing for the visit
- Let us know about earlier repairs to the joints
- Mention any leaks or damp you’ve noticed
- Try not to wet indoor joints just before the visit
Ask for a quote
Call for a quick quote, or email us if that’s easier. Tell us about the joints that need doing and we’ll explain what’s involved.
Read more
DIY versus a professional finish
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Your questions about remedial sealant in Blackmore End
Do you work for landlords with property near Harpenden station?
Yes. We work for landlords and agents as well as householders. You can ring 0345 464 0079 or send us an email with the details for a clear quote.
Do you cover smaller places like Blackmore End?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
How long before the joint can be used?
That depends on the sealant used, so follow the cure time we give you when we finish.
Can you match the sealant colour?
We help you choose a colour that suits. The product needed can limit the range.
Where is Mr Mastic based?
Our base is in Crawley, West Sussex, and we work across South East England, London and Scotland.
Can you remove sealant that’s been put over old sealant?
Yes. We remove every layer; new silicone doesn’t bond to old silicone, which is why over-sealing fails.
Someone resealed my shower and it’s leaking again. Can you help?
Yes. There’s generally a reason: sealant over sealant, movement or another leak, so we find that first.
How much does remedial sealant cost in Blackmore End?
Size, access and the old material all affect the cost. Ask us for a quote and we’ll talk you through it.
Work for landlords, hotels and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
From a single let to a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a one-year guarantee.
Blackmore End homes and their sealant
Most of the South East has hard water, so limescale builds up on sealant, grout and fittings.
In the older streets around St Peter, walls and floors in older homes can move, and sealant and grout show it first. Schools such as Kimpton Primary School are buildings too, and its toilets, changing areas and kitchens need their sealant renewed like any other building’s. Letting a property close to Harpenden station? Then failed or mouldy sealant is worth putting right between tenancies, before it turns into a leak.
Blackmore End is about 2 miles north-east of Harpenden, in Hertfordshire. Every kind of property in Blackmore End can book us for remedial sealant. Every job comes with our 12-month guarantee. Our area takes in 381 places across Hertfordshire, large and small. Our London page covers work nearby.
Our applicators cover all of the AL4 postcode area for remedial sealant and the streets around it. You will find streets such as Kimpton Road, Beech Way and The Drive, and we cover them all. Other places close to Blackmore End include Porter's End (1 mile north-west), Mackerye End (1 mile south-west), The Folly (1 mile south), Lea Valley (1 mile south-west) and Bower Heath (2 miles west). Within a short drive, we also cover Watford (13 miles south), Hemel Hempstead (9 miles south-west), Stevenage (7 miles north-east), St Albans (6 miles south), Welwyn Garden City (5 miles south-east) and Hitchin (8 miles north).
Near you in Blackmore End
Locally, jobs take us to homes and businesses close to Cross Keys Public House and Sir John Lawes School, among other places. Blackmore End’s nearest station is Harpenden station, roughly 2.6 miles south-west of the centre. Well-known places in the area include St Albans City Hospital (5.6 miles south) and Harpenden Museum (2.9 miles south-west). Green spaces nearby include Stocking Springs Wood.
Nearby places to Blackmore End
Other services in Blackmore End
What we can’t put right
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- A cracked shower tray or bath (that needs repair or replacing)
- Older mastics that may need an asbestos check before removal
- Movement from fittings that aren’t supported
If you’re not sure, just call 0345 464 0079 or drop us an email and we will give you a straight answer before you book.
Where we work in Blackmore End
- Expansion joints
- Mouldy bath & shower sealant
- Failed movement joints
- Botched or over-sealed joints
- Shrunken worktop sealant
- Leaking tray & enclosure joints