Portsmouth · England
New Build Mastic in Portsmouth
New build mastic for Portsmouth, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Plot mastic for developers ahead of handover
- Worktop and upstand sealant coming away
- New-build shower sealant that has already split
Honest limits
Before booking, it’s worth knowing the limits:
- Deciding who is responsible under a builder’s warranty
- Plumbing faults behind the sealant
- Movement caused by a poorly fitted tray or bath
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we’ll tell you honestly.
Where we work in Portsmouth
- Show homes
- Kitchens
- Plot handovers
- Skirting & floors
- Windows & doors
- Bathrooms & en suites
About our new build mastic in Portsmouth
If your new home has a leaking shower seal, open skirting joints or untidy sealant, we can help. While the builder’s snagging or warranty period runs, report it to them first. Typical jobs include untidy sealant flagged on a snagging list and leaking shower tray seals in a new home, across show homes, kitchens and bathrooms & en suites.
Portsmouth is big enough to have new developments going up alongside its older streets. Snags in sealant and floor joints often show in a new home’s first year or two.
Each job carries a 12-month guarantee.
- Place
- Portsmouth (PO6, PO4, PO1, PO2)
- Region
- Portsmouth
- Guarantee
- One year on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Portsmouth: your questions answered
Can you help a landlord with a rental near Fratton 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 email us with the address and what needs doing, and we will give you a clear quote.
What guarantee comes with new build mastic in Portsmouth?
All our work, in Portsmouth and everywhere else, comes with a 12-month guarantee. We’re also fully insured and ARBOMaster approved.
How long should I leave it?
That depends on the sealant used, so follow the cure time we give you when we finish.
Where are you based?
We are a Crawley-based firm. Our area covers South East England, London and Scotland.
Do you work for developers?
Yes. We work through plots to your schedule, room by room. Get in touch with the number of plots and the scope and we’ll quote.
Why does sealant fail so quickly in new builds?
It’s common, and there are generally two reasons: the house moving as it dries, and sealant that never bonded properly. Cutting it out and resealing properly fixes both.
Do you cover Portsmouth?
We do. Our applicators work in Portsmouth, and the service is the same as everywhere else.
How long will you be here?
A typical job takes a few hours for most snagging lists, longer for a run of plots. Your quote will say how long we expect yours to take.
DIY versus a professional finish
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.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
What else we do in Portsmouth
What happens on the day
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. Typically it takes a few hours for most snagging lists, longer for a run of plots. For homes and businesses in busier parts of Portsmouth, parking needs a little planning. For flats, mention stairs, lifts and shared entrances as well.
- We start by going through the snagging items or plot schedule with you.
- Every bit of the old builder’s sealant is cut out.
- Joints are vacuumed and cleaned of building dust.
- We prime where needed and apply a sealant suited to each joint.
- Each bead is tooled and the cure times explained.
Before we arrive
- On commercial sites, let us know about site rules
- Mention any parking rules near the property
- For indoor joints, keep the area dry beforehand if you can
Get a quote
Asking for a quote is easy: tell us what needs doing and where and its rough size. Photos by email help us understand the job, and we will take it from there.
Related advice
What the job involves on each surface
Skirting and floors
New homes often develop a gap between skirting and floor. A flexible sealant closes it without cracking like caulk.
Show homes
In a show home, the sealant is on display. We lay neat, even beads in colours to suit the finishes.
Keeping the joints in good condition
Aftercare is simple:
- Don’t seal over failed sealant yourself
- Keep photos and emails about snagging items
- Open a window or run the fan after bathing
- Check bath and shower seals every few months as the house settles
Keep the bathroom ventilated, especially in the first year. Run the fan or open a window after bathing.
Leave a failed new-build seal and water can reach the floor and the ceiling below. Early resealing keeps the job small and protects the rest of the house.
New homes and floors in Portsmouth
Portsmouth is close to the coast. New homes near the sea put their outside mastic to work from day one, so any gaps are best picked up early. Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For new homes near Fratton station, it’s worth checking the sealant early, while snags are still fresh.
Portsmouth is in England. Every kind of property in Portsmouth is covered for new build mastic, old or new, large or small. Every job comes with our 12-month guarantee. 19 places in Portsmouth are on our list, from the larger towns to small villages.
Our applicators cover all of the PO6, PO4, PO1 and PO2 postcode area for new build mastic. You’ll find streets such as Church Road, April Square and Rudmore Square, and we cover them all. Portsmouth sits on or near the A3 and A27. Other places close to Portsmouth include Rudmore (1 mile north-west), Landport (1 mile south-west), North End (1 mile north), Fratton (1 mile south-east) and Kingston (1 mile south-east). Larger places within reach include Wymering (3 miles north), Paulsgrove (3 miles north), Drayton (3 miles north-east) and Farlington (3 miles north-east).
Around Portsmouth
Typical jobs here are in homes near The Portsmouth Academy, Alexandra Park and St Edmund's Catholic School, among other places. The closest station to Portsmouth is Fratton station, about 0.9 miles south. Other landmarks nearby include Royal Portsmouth Hospital (0.7 miles south-west) and Charles Dickens Birthplace Museum (under half a mile west). Open spaces near Portsmouth include Milton Locks and Portsdown Hill.
How we quote for new build mastic
Every job gets its own quote. These are the things that affect it:
- The product the joint needs
- The number of rooms or windows
- How easy the joints are to reach
- When we can work, for business premises
No two jobs are quite the same, so each one gets its own quote. The number of joints, how easy they are to reach and the sealant needed all play a part, and we’ll explain the quote if you ask.
What we need to know
When you call or email, these details help:
- Pictures of the joints, sent by email
- If it’s domestic, commercial or a hotel
- The problem you’ve noticed
- The rough size of the job
We quote each job on its own, so the first step is telling us about yours. Simply call 0345 464 0079 or send us an email and describe the job.
Do you need new build mastic in Portsmouth?
Sealant applied onto damp surfaces does not bond well. On a busy site, joints are not always given time to dry.
Look out for these signs:
- New-build shower sealant that has already split
- Gaps behind new kitchen upstands
- Frame joints opening as the plaster dries
- Gaps between new skirting and floors
In and around Portsmouth, as anywhere, good new build mastic starts with a clean, dry, properly prepared joint.
What your quote should include
- Which colour the sealant will be
- Who does the work, and how experienced they are
- Whether all the old sealant comes out first
- When the joint can take water or movement