Most houses and buildings have the heights set up to require flooring of a certain thickness. For example, a specific height has been allowed between the subfloor and the bottom of your internal doors for your floor coverings.
If you plan to glue down your timber floor we recommend allowing an additional 2mm on top of the thickness of your floor for glue. E.g. Thickness of floor covering + 2mm allowance for glue = total floor height allowance. Alternatively, if you are floating your timber floor you will need to allow for the thickness of the underlay you plan to use. E.g. Thickness of floor covering + allowance for underlay = total floor height allowance
If you are yet to have your plans drawn or they are in progress
The floor height shouldn't be an issue - as long as you tell your architect what thickness of flooring you choose (+ glue or underlay allowance) and they can incorporate it into the plan
If you are in the early stages of building
You should check with your builder to see what thickness of flooring has been allowed for. Bear in mind you need to deduct the allowance for your glue or underlay (depending on whether you are gluing down or floating your floor) from the thickness that has been allowed for. You could also ask how difficult this would be to change if you decide you want a different thickness of floor covering. If this is an option, you are not limited by product thickness but if it's not you need to stick to what your plan specifies.
If you are in the later stages of building
The floor coverings you choose, plus your glue or underlay allowance will likely need to add up to the floor height that your plan specifies. Ask your builder if you are unsure of the details.
If you are removing & replacing the old floor coverings
It is easiest to choose a product that together with your preferred glue or underlay makes up the same thickness as your old floor covering. If you opt for a thicker product you will need to trim the bottom of any doors in the areas where you are installing the product.
If you are installing the new floor coverings over your old floor
You will need to trim the bottom of any doors in the areas where you are installing the product. It may be a good idea to opt for a thinner floor covering option so you don't have to take too much off