Bathroom Design Basics (Everyone Should Know)…

I get asked a lot what the pitfalls of bathroom design are for designer’s who are just starting out in the business and I would have to say that bathrooms and kitchens are by far the hardest if they have never experienced renovating their own or a friend’s first!

Kitchen’s are a whole other ballpark and come with many, many opportunities for mistakes for the unwitting, fresh designer, so I thought I would start with bathrooms as we could fit this into one blog post!

There are a few key areas that are really important with bathroom design and refurbishment that are really important to highlight to a novice who has never undertaken a project like this before. Often, an interior designer will eventually get asked to design a bathroom for a client and they will say yes, then think “its just about choosing tiles and a suite, right?”

Finishes

• Walls – This is possibly the trickiest thing to consider when undertaking a bathroom renovation or design as the first thing to consider is how much space you have for finishes! If the architraves are staying (as they will most likely do in a low cost or budget renovation), then you will need to measure how deep they are so that you can design around the doors and windows.
• Floors – Next, unless you want a “lovely” toe scratching metal bar or even worse, a toe breaking step up into the bathroom, you will need to understand what the juxtaposing floor finish is going to be (or is) and how deep that is too. Whilst you’re at it, if your client hasn’t got a big budget to ask the carpenter to cut the door to fit your 30mm stone flooring, then you might want to measure how much gap you have under the door too, just to make sure you know how much space you have to play with.
• Ceiling – If you can’t measure the void within the ceiling or can’t photograph it, then think about whether the property is a flat and what floor it is on. You may need to consider fire-hoods / casing and some LED lighting will have large heat diffusing backs and or may require transformers in an accessible place, close to the lights themselves. Don’t forget that bathroom lighting in Zones 1 and 2 needs to be IP44 rated minimum (Zone one is the area in the bath, shower or around the sink and Zone 2 is the area around those areas up to about 60cm – which is more of a splash zone).

Just as a rule of thumb, I would look at the thickness of what I am proposing (the depth of the tile or stone) and then know that I will probably need around the same amount of space behind the tile to fix it in place. Usually, a 3mm tile can get away with a much thinner bed, but a 20mm piece of stone will need at least 10mm bed with at least a cementitious board that can carry the weight of the stone.

Don’t forget that not all wall tiles can be used on the floor either. Ceramic tiles which are usually cheaper will usually be only for the walls as they are much softer than porcelain tiles or stone, so always check before making your final decision on your finishes.

Photo by Jared Rice on Unsplash

Drainage

I used to get teased in offices I worked in because I actually am a total geek with drainage and love working it out. I used to get a lot of the s**t jobs passed to me as I genuinely enjoyed them! I love drainage! I even considered changing careers at one point to re-train as a plumber (then I realized I have a very sensitive nose…)

Drainage is one of those things that if you don’t know what you are doing, then leave it alone and don’t mess with it. The cheapest thing with a bathroom is to leave the pieces where they are and replace them like for like. Even something as simple as changing a bath to a shower can cause problems, as a shower trap will need to fit in the floor and that isn’t always possible on a refurbishment. That is why you see those poor showers that need stepping up in to (oh the humanity!)

The key with bathrooms, however, is looking at where the riser is. You’ll spot it easily in an older building as it will probably be boxed out, but in a new building, it will most likely be concealed slightly better (you’d hope). The toilet is usually positioned pretty close to it, so that is your first give away. Moving a toilet or shower around the riser is usually not too much of a problem because the proximity to the connection is the key.

As a rule of thumb, a shower waste will be around 50mm and a toilet waste pipe will be around 110mm in diameter and they require a fall to the riser of 1:60 (that’s 1 meter in height for every 60m in length – or about 2cm drop per meter. That doesn’t sound like much, but considering the floor depth is usually around 250mm, then you start to encroach on the ceiling below if moving it more than a couple of meters.

Although that still doesn’t mean you can move them because it also depends on what the floor or ceiling structure is made from. If you are dealing with a timber floor and the joists are running in the right direction, (check the engineer’s or architects drawings) you can get lucky and you can run the pipes within the floor, but if your joists are running in the wrong direction and you don’t have a ceiling void below, you will have to alter your layout (or opt for a syphoned toilet…)

Sanitary Fittings

Ah, the joy! Just when you find the perfect shower in the right finish, you can’t match the mixer, or just when you find the perfect set for everything it doesn’t have WRAS approval. This can be a minefield and unless working on super low-cost projects are often best dealt with a contact or supplier from a specific company. There are so many parts and mechanisms that go along with and need to be ordered to fit a shower or tap that it is best to work alongside someone who knows their stock.

This is the kind of thing you don’t really want to leave to your plumber. Low-cost projects usually do and that is where you start to get mismatched items or showers not working well. If you know it, you will also need to know the pressure you currently have and the type of system in your property. A gravity led system has much less pressure than mains pressure and you may need to also install pressure reducing valves (for the designer that means fitting more things in behind the already full walls or hiding more stuff or trying to box it in).

What I’m trying to say is that choosing a shower head and matching mixer is not as simple as matching the style to the mixer on the basin. There are a lot of things that are needed to be considered alongside the items themselves to make sure they work correctly once installed. Add to this water reducing filters and water saving devices you have to really know what items will work to give you the desired end result.

Before choosing sanitary items and before speaking to the manufacturer (you always should before ordering to make sure you are specifying the right parts) make sure you have to hand the following things:

1. The type of boiler and hot water installation (ie mains or gravity pressure).
2. Water saving or regulatory requirements (usually only for new builds or historic projects) or any unique property specific requirements.
3. The depth of the walls, floors and ceilings and construction type for installation and fixing – sometimes noggins or ply need to be inserted into the wall to fix the mixers, towel rails etc.)
4. Depth and profile of the finishes (Eg. a highly profiled tile can look terrible with a flat plate for a mixer stuck on it, no matter how aligned it is!)
5. Which direction the floor and ceiling joists run (if timber construction) and where the wall studs are.

And just one final note, don’t expect to be able to use an external wall depth to add to the room you have. External walls should not be messed with, especially in new construction where any penetration could affect the airtightness or vapour control of the building. As a general rule, if you want to hide some piping in an external wall, you will need to build a new wall or boxing in front of it so that you don’t damage the external envelope of the building which could cause damp or allow vermin into the walls. Refurbishments are where most of the big mistakes happen because the initial build is tightly controlled but small or minor works in between aren’t usually monitored and often done by uneducated homeowners, on the cheap or in a DIY way.

Buildings are getting more complicated and there are more things that can be damaged than just a bit of mould getting through a wall. Partitions, floors and ceilings all act as fire compartmentalization so some alterations, if not completed by a competent person who knows the local laws may be unknowingly creating a dangerous situation.