Drawing a house – Common mistakes owners make

Drawing a house – Common mistakes owners make

I often get calls from people who want to build on, and have drawn up plans for what they want. This helps a lot, since the owner can visually show me what he expects of a building plan. However, there are a lot of mistakes that these owners make, and often this impact hugely on their expectations.

Forgetting that walls have a thickness
As a first example, the owner will go into the yard and measure up how much space he has to work with. So let us say that there is ten meters of length to work with. When drawing, he will draw a line of 100 millimeters long, representing this length. Now he makes the crucial mistake of forgetting that walls have a thickness. In 10 meters, he sees that he can fit in a room of 3 meters long, another of 3 meters long and another of 4 meters long.
Allowing that the original house will probably just be extended and there is thus already one wall (of the original house) in place, it still means that he must build two interior walls and one exterior wall, and this can mean as much as 460 mm. That is almost half a meter of space that is going to go missing from his plan, a disaster if he thought he was going to have a large main bedroom.

Not taking stairs into consideration
Another common plan that owners have is to build up, especially if their garden is small and there is not much room to go sideways. Here I have seen elaborately concocted plans, often with the fatal flaw of not taking into consideration that you need stairs to get to the upper floor, and stairs take up a lot of space.
Depending on how high your ceiling is going to be, you will need about 18 stairs. With a stair tread of 340 mm and a width of 900 mm, that is a lot of space you need. (You can get stairs with less tread, but it makes for very uncomfortable walking – Beware!)

Roofing and rainwater
Whether your garden slopes or not, you are going to have to deal with rainwater, and it is all too easy to design a house with large areas where the rainwater has nowhere to go. This means the rainwater will either go through your house, or it will dam up somewhere and cause damp. Check the fall of your garden carefully, especially during rain storms, to see what the water does, before you build yourself an unwanted and expensive dam.

Toilets that are visible
This really is one of my pet peeves. I have been in a number of very new and very modern homes that looks fantastic right up to the point where I notice a door leading off the lounge and/or dining room, only to discover that on the other side of that door hides a toilet.
There is no amount of fancy interior decorating that is going to make an unsightly toilet go away, so if you are designing your own place, please remember that there should not be a line of sight from family gathering areas to a toilet.

Forgetting about the sewer system
I know that sewer systems are not something that people like thinking about, but it is and remains one of the most important features of your house. If your sewer system stops working, your whole house becomes a nightmare.
When planning your additions, take careful note of where your current sewer system runs. Ensure that you don’t plan on building over cleaning eyes, that there is enough space for the new system, and that any gulleys and vents are not closed over. If needs be, you might have to move some parts of the system completely.

Any other problems?
Walk around your existing house and yard, and try to imagine your new additions already in place, with an eye on seeing where the pitfalls might be. This will stop some frustration on your part when the draughts person gets to see your plans, and giving you some nasty surprises!