Putting a Bathroom in an Upstairs Extension

Two storey extensions are gaining in popularity as the state of the housing market in the UK continues to persuade people to extend rather than move house. And putting another bathroom in a family house, whether it’s an en suite or a family bathroom, makes excellent sense.

Upstairs Extensions Gaining in Popularity

Putting up a two storey extension is becoming more normal for a number of reasons. Firstly the cost of building has come down in real terms over the decades. The proportion of the cost involved in adding a second storey, compared to the cost of a single storey extension of the same footprint, is nowhere near double.

This is because a large proportion of the cost of an extension goes into the foundations and the roof. So the increase in cost of adding an upstairs extension to a single storey project is more likely to be around a quarter to a third more The level of disruption isn’t much greater, the planning costs are generally the same, and the value added onto the house is higher.

Looking at the Pros and Cons

From a purely financial perspective the space in an upstairs extension would probably be better off used as a bedroom. You’d save the expense of all the bathroom equipment, plumbing and labour, and the peculiar fixation on bedroom numbers, when valuing houses in the UK, would increase the value of the house.

But it’s not that simple. If you turn, say, a four bedroom house into a six bedroom one without putting another bathroom in it might make the house difficult to sell. Developers are increasingly putting two bathrooms, an en suite and a family bathroom, in even the smallest of houses, and you have to compete with them.

You also need to take into account the price ceiling in your area. For example if all the houses in your street are three or four bed homes then the maximum price of a home in that street will be closer to the four bedroom houses regardless of how many bedrooms you add.

Practicalities of a Bathroom in an Upstairs Extension

Having assessed all that if you decide to put a bathroom in an upstairs extension the first thing to do is look at where the plumbing goes in you house. Go outside and look where the waste pipes from existing toilets and bathrooms are. Then look at where any existing bathrooms are and how far away the hot water tank is (if there is one).

The closer the new bathroom in the upstairs extension can be to an existing bathroom then the easier, quicker and cheaper the building work will be. If there isn’t an existing bathroom upstairs then try and site the new bathroom over the kitchen, or as close to that as you can get.

Note that if there isn’t an existing bathroom upstairs then the hot water tank may be downstairs as well. If that is the case then you will have to install pumps to get the hot water up to the new bathroom or install a hot water tank somewhere upstairs or in the loft. Alternatively you can look at newer boilers that heat water on demand and don’t need a tank.

Dealing with Long Distance Pipework

If you can’t get the new bathroom close to any existing pipework and waste disposal then all is not lost. Using lightweight and flexible plastic piping for hot and cold water you can supply a bathroom in an upstairs extension almost anywhere, although you may need pumps or extra tanks to provide sufficient hot water pressure.

As far as the waste goes you can use micro-bore pipework which again is made of flexible plastic. To deal with the waste install macerators which grind it into pieces small enough to pass through the micro-bore piping.

Measure for Measure

Finally there’s a little trick that you need to be aware of when putting a bathroom in an upstairs extension. Measure the stairway and any other doors to make sure you can get the bath up there!