Adding an En-Suite to a Bungalow or Loft: Plumbing, Drainage and Space

An en-suite is one of the most popular additions to a home, and it comes up again and again in bungalows (which often have just one bathroom) and in loft conversions, where a new bedroom upstairs is far more useful with its own shower room. Around Cromer, Sheringham, Holt, North Walsham and Norwich, it is often the thing that turns a good conversion into a great one.

The tricky part is rarely the tiles or the taps. It is where the water goes. Here is what to think about before you commit to a layout.

Where should the en-suite go?

The best place is usually the one closest to your existing soil stack (the large vertical waste pipe) or drainage run. Putting the en-suite back-to-back with an existing bathroom, or in a loft directly above the bathroom below, keeps the pipework short and simple.

It also needs to be big enough to use comfortably. As a rough guide, a shower is most comfortable from around 800 mm square, and you want about 600 mm of clear space in front of the WC and the basin. A sliding or pocket door can save a surprising amount of room. The aim is a usable en-suite without leaving the bedroom too small.

Getting the waste to the soil stack

A WC needs a 100 mm waste pipe with a steady fall to the soil stack. Showers and basins use smaller pipes, but they also need a fall, and Building Regulations limit how long and how steep these runs can be. That is why the position of the WC matters most.

• In a bungalow, the floor is often a concrete slab. Running a new waste pipe can mean cutting a channel through the slab, or raising the shower tray on a low platform. Suspended timber floors are usually easier. A new connection into the drains outside may also be needed.
• In a loft, the pipes run between the new floor joists and then down to the stack. Sometimes a new soil stack is needed, either boxed in inside or fixed to the outside wall. Where the drainage is vented elsewhere, an air admittance valve can sometimes avoid taking a vent pipe through the roof.

What about a macerator toilet?

A macerator (a pump that grinds and pumps waste through a small pipe) can make an awkward layout possible. But Building Regulations guidance only allows a pumped WC if the house also has a WC that drains by gravity, and the unit must meet the right British Standard. Macerators also make some noise and need occasional maintenance, so they work best as a second toilet, not the main one.

Ventilation, hot water and electrics

• Extractor fan. Building Regulations (Approved Document F) ask for a fan that extracts at least 15 litres per second from a room with a shower or bath, ducted to the outside. Most are fitted with a run-on timer.
• Hot water and pressure. Check that your boiler or hot water cylinder can cope with another shower, especially if two might run at once. A shower at the top of the house may need a pump if your system is fed by gravity.
• Electrics. Bathrooms have special zones for lights, fans and shaver points. New bathroom electrics must be done by a registered electrician or approved by Building Control.
• Waterproofing. Walls and floors around showers should be tanked (waterproofed) behind the tiles, particularly for walk-in showers.

Do you need permission?

A new en-suite inside your home doesn’t usually need planning permission. Building Regulations do apply, because of the new drainage, ventilation and electrics, so the work needs Building Control approval or certificates from registered installers. If the en-suite is part of a loft conversion, it is covered by the loft’s Building Regulations application.

In a listed building, internal changes need listed building consent — see our page on listed buildings. In a conservation area, a new soil pipe on the front of the house may need planning permission, so check with the council first.

How much does an en-suite cost?

National 2026 price guides put a straightforward new en-suite at roughly £3,500 to £8,000, with most homeowners spending between about £4,500 and £12,000. A loft en-suite, or one that needs a new soil stack, is often £10,000 to £15,000 or more. Building new stud walls, moving a door or cutting through a concrete floor adds to that.

An itemised quote should show the building work, plumbing, electrics, tiling and sanitaryware separately, so you can see where the money goes. Our guide to builders’ quotations explains what to look for.

Need level access or room for a wheelchair? That is a different design — see our wet rooms and accessible bathrooms page.

Planning an en-suite with Stellar Construction

We often plan en-suites as part of loft conversions, house extensions and renovations. Getting the layout right at the start, around the drainage, saves money later. You get one point of contact from start to finish and a clear, written price.

Book a free quote or call us on 01692 763300.

Frequently asked questions

Can I add an en-suite to a bungalow with a concrete floor?

Usually, yes. The waste pipe can run in a channel cut into the slab, or the shower can sit on a low raised platform. Keeping the WC close to the existing drainage makes it much easier.

Do I need Building Regulations approval for an en-suite?

In most cases, yes. New drainage, extractor fans and bathroom electrics are all covered by Building Regulations, either through Building Control or registered installers.

Can I use a macerator toilet in an en-suite?

Yes, as long as the house also has a toilet that drains by gravity. It is a useful fix for awkward layouts, but a gravity WC is the better choice wherever it is possible.