Hampshire · England
New-build mastic & snagging in Blackwater, Hampshire
Professional new build mastic in and around Blackwater, with old sealant always removed completely and a 12-month guarantee.
- Shower seals failing in the first year or two
- Internal frame sealant that has split
- Gaps opening as the house dries out and settles
Common problems we fix in Blackwater
Fresh sealant can be knocked or cut by trades finishing off. If it’s disturbed before curing, the joint can be left weak and it shows once the home is in use.
If you can see any of these, it’s time to have the joints looked at:
- Beads laid onto grit and dust from the build
- Gaps behind new kitchen upstands
- Skirting joints opening in the first winter
- Joints pulling apart as timber shrinks
For new homes near Blackwater station, it’s worth checking the sealant early, while snags are still fresh.
What your quote should include
- Is the old sealant removed completely?
- Is VAT in the price?
- What preparation is included
- Who does the work, and how experienced they are
About our new build mastic in Blackwater
New homes move as they dry out. Timber dries and shrinks, and baths and trays settle, and sealant applied in a hurry at handover can split. We work on plot handovers, windows & doors and show homes, and people most often call us about worktop and upstand sealant coming away and shower seals failing in the first year or two.
Where new homes go up in smaller places like Blackwater, it’s often a small development or a single plot. The sealant around baths, showers, frames and skirtings needs to be right from the start.
A 12-month guarantee comes as standard, so you’re not left on your own once the job is done.
- Where
- Blackwater (GU17)
- Wider area
- Hampshire
- Guarantee
- 12 months on all our work
- Price
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Honest limits
It helps to know what we cannot do too:
- Cracked trays, tiles or worktops
- Leaks from pipes, valves or wastes, which need a plumber
- Disputes or warranty claims with your builder
Not sure which it is? You can ring 0345 464 0079 or send us an email and we’ll tell you honestly before booking.
What we seal
- Kitchens
- Skirting & floors
- Show homes
- Bathrooms & en suites
- Plot handovers
- Windows & doors
Keeping the joints in good condition
After the cure time, these simple habits help:
- Act quickly if a seal starts to leak
- Record problems with dated pictures
- Wait for the cure time before using a resealed shower
- Check bath and shower seals every few months as the house settles
Follow the cure time we give you before the area gets wet. Most silicones need around a day to cure enough for use.
Mould takes hold quickly in sealant that has gaps or lifted edges. Dealing with it before it goes black saves a harder job later.
How it works
We keep the work tidy and contained to the joints we’re treating, so you can get on with your day. The job normally takes a few hours for most snagging lists, longer for a run of plots. For a job in Blackwater, we agree the time, the access and parking before the day. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- First, the list of joints is agreed from your snagging sheet or plot schedule.
- Every bit of the old builder’s sealant is cut out, with no layer left behind.
- We clean out the dust and grit left from the build.
- We prime where needed and apply a sealant suited to each joint.
- Each bead is tooled and the cure times explained.
Before we arrive
- Where the joints are inside, avoid wetting them before we arrive
- Mention any leaks or damp you’ve noticed
- Keep pets and children clear of the area while we work
Ask for a quote
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we’ll talk you through the work.
Related advice
DIY versus a professional finish
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. All the old material has to come out first.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly, so tell us about it when you ask for a quote.
How we quote for new build mastic
We do not publish a price list, because jobs vary so much. What we look at:
- How much old sealant there is and how hard it is to remove
- The size of the job
- The number of rooms or windows
- The type of sealant required
No two jobs are quite the same, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference.
What we need to know
Photos by email are helpful but not essential. Please mention:
- Whether it’s a home or a business
- Pictures of the joints, sent by email
- Where the property is
- Access, such as stairs, a lift or height
Want a quote for new build mastic? Please ring 0345 464 0079 or drop us an email with a few details. We will explain what we’d do and send you a clear quote before any work starts.
Also in Blackwater
For landlords and businesses
Letting agents and landlords in Blackwater can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for.
For anyone letting property in or around Blackwater, several properties can go on one quote. Just tell us the addresses and what each one needs, and pictures by email help.
FAQs for Blackwater
Will you come out to Blackwater?
Yes, Blackwater is covered. 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 Blackwater station. Can you help?
Yes, we work for letting agents and landlords. You can call 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before any work starts.
How long does new build mastic take?
As a guide, most jobs take a few hours for most snagging lists, longer for a run of plots. Bigger jobs take longer.
Can you quote for more than one area?
Yes. Just list everything you need.
Do you take on second-fix sealing for builders?
Yes. We carry out plot mastic and second-fix sealing for builders and developers. Send us the plot schedule and we’ll quote.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator, and we are fully insured.
Is it messy?
Very little: the area around the joints is protected first, and we tidy up before we go.
New build mastic in Blackwater: local notes
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
In and around Blackwater, as anywhere, good new build mastic starts with a clean, dry, properly prepared joint.
Blackwater is about 1 mile south of Sandhurst, in Hampshire. Homes, rented property, offices and hotels in Blackwater is covered for new build mastic, old or new, large or small. Every job comes with our one-year guarantee. Our area takes in 683 places across Hampshire, from the larger towns to small villages. For nearby work, see our Reading page, about 11 miles away.
We work across the GU17 postcode area for new build mastic. That includes homes and businesses on London Road, Bell Lane and Ash Close. We also cover the places around Blackwater: Frogmore (1 mile west), Hawley (1 mile south-east), College Town (1 mile north-east), Sandhurst (1 mile north) and York Town (1 mile east). Larger places within reach include Basingstoke (14 miles west), Farnborough (3 miles south), Fleet (5 miles south-west), Aldershot (6 miles south), Alton (15 miles south-west) and Tadley (15 miles west).
Local landmarks in Blackwater
Typical jobs here are in homes near Mr Bumble pub, Frogmore Community College and Royal Military Academy Library and the streets around them. The closest station to Blackwater is Blackwater station, roughly 0.6 miles east. Other landmarks nearby include Frimley Park Hospital (2.4 miles south-east) and Staff College Museum (1.9 miles east). The countryside around Blackwater includes Horseshoe Lake and Ball Hill.