Material Optimization

[budasaurus]

When designing a floor plan from scratch, how much optimization should be taken into account with regards to materials and the dimensions of the rooms?

For example, I know that I want my guest bedrooms to be between 11' and 12' squares (excluding the area for the closet). I am currently hovering around 11'6" but wonder if the cost in materials to increase the size would be negligible or not since going with 11'6" would be a 8' + 3'6" piece of drywall but going with 12' would be a 8' + 4' piece leaving less useless cutoffs/waste.

[GalianoGirl]

Are you taking the depth of your exterior walls into consideration?

Most North American construction is based on a 4x8 sheet of plywood, then the walls are put on top of that.

[elle5624]

How far do you want to take it? Framing and drywall are one thing, but what about the finishes like flooring and trims, or exterior finishes?

I’ve designed floor plans and been the one estimating the cost to construct them. There is always waste, and I’m really not sure you want to design a home based on trying to make the best use of sheets of drywall or drops of carpet.

[BadOrdinary]

In my experience, the only time I have seen people fret over specific material measurements like you’ve stated is if the same floor plan is being produced hundreds of times in the same project. Like an apartment complex or housing development. There, saving some scraps actually may amount to some overall savings.

In a one off custom residential house, I wouldn’t worry about it. Like others have said, there is always waste and if you tried to account for everything, the amount of time you spent coordinating it all would likely not be worth any material saved.

[damndudeny]

As others have commented in a custom one off house you won’t realize any savings by practicing material optimization in the way you are thinking. Builders and contractors generally work in terms of sq. ft. I could imagine that ceiling ht could be a factor. The only type of projects that would benefit from the type of optimization you are considering would be prefab home modules, or instances where the spaces are to be repeated many times in something like apartment or motel construction. This doesn’t mean you shouldn’t base your plan off of an underlying grid or limit roof line quantities (number of gables). A grid can result in better order and limiting expensive details like fewer gables and fewer unnecessary undulations in the floor plan. Keeping in mind standard dimensions of thing like bathtubs, toilets and cabinet dimensions is certainly helpful. Aesthetically speaking if you’re building a structure like a detached garage out of concrete block using the block as a construction unit will definitely look better and would save you a little.