What is the width of a house in meters?

This cannot be answered without more information.

No it can't, and I'm amazed how many enquirers seem not to realise that.

However, I suspect this enquirer really wanted to know how to convert the dimension from feet to metres. (That is the right spelling - it's a French invention and Word.)

If so, 1 metre = 3.280 feet or 1 foot = 0.305 metre.