What size do most use?.....

There’s no standard for built-ins. Lower kitchen cabinets are 24” deep and uppers are 11 3/4” IIRC. Most bookshelves are ~12-16” deep.

Kitchen countertops should overhang cabinets by 1.5” or so. But again, that’s for kitchens.

What jonah said ^^

I was thinking 20” deep for the cabinets and 12-15” deep for the shelves….

-- Hey you dang woodchucks, quit chucking my wood!!!!

The bottom sections of built-ins like this
are usually shallower than kitchen cabinets.

20” deep is sensible.

Years ago my shelves would end up being 12”.
11” shelving, 1/4” luan back and 3/4 for face frame.
Years ago the base cabinet needed to be wide for those big deep tv’s but that’s not a problem, now a days.

-- An Index Of My Model making Blogs https://www.lumberjocks.com/htl/blog/130264

Upper and base can be any size. There is no set standard for this. usually there is a plug along the side wall that sets the depth on many bases.

As far as counter tops….There usually 25” residential and 25” commercial. Blanks are sold 25”x144” just for this purpose…

Paint or stain?

First I would consider what are going on those shelves. Usually books are the the usual items. Look at the size of the biggest books that you intend to put on them and size the depth of the shelves accordingly.

I assume you are going to make them adjustable shelves. When I built my bookshelves/shoe storage project I used saw-tooth shelf adjusters.

As for the bottom cabinets, again I would determine the depth by what I wanted to store in them. In the bookshelves/shoe cabinet I built, it was determined by the tilt-out shoe storage containers.

Your 20” deep cabinets and 12 inch shelves sounds good to me.

You might want to consider including full extension low side shelves … depending on what you intend to put in the cabinets. It will make getting to the items in the back of the deep cabinets easier.

You should also consider a toe kick at the bottom 3-4” deep.

If you live near a furniture store or an IKEA store, take a tape measure and see what dimensions you find as a guide.

Hope that helps.

-- Tyvekboy -- Marietta, GA ………….. one can never be too organized

If the built in is meant as an entertainment center, be sure the TV area is big enough for future expansion in the size of the TV. Nothing like sizing the cabinet for your current TV and then not being able to go bigger ever because the built in can’t fit anything bigger. Calculate the physical size of the largest TV you could see yourself owning and go with that. Also, be sure cabinets meant for components/game systems have a way to get air in and out. Those things generate a lot of heat. I’d put ventilation holes or even a big cut away along the red line to let air out of the lower cabinets.

If you are putting books on them a 10 inch wide shelf is plenty, unless you are dealing with oversized books.

Remember this is custom and you are building it for your things. Forget about standard, and what everyone else is doing.
How big are the things that you want to put on it?
Is it paperback romance novels or oversized art?

That is where you need to go to find your answer of how deep the shelves should be.

-- nice recovery, They should pay extra for that mistake, Eric E.

Alot of good advice above, including Jonah’s comments about ventilation for electronic components you plan to store inside cabinets.
Measure your components depth and make you sure you allow room for any connecting cables that will stick out the back of your components (receiver/DVD/etc). I built one with inside depth of 15” which was just barely enough. Your 20” cabinets and 12-15” shelves should work well.

-- Rick - I know I am not perfect, but I will keep pressing on toward the goal of becoming all I am called to be.

The is pretty much and open book on something like that . Design it around what you want to put on it/in it, your budget and material use. Shelf spans are important. Are your shelves going to me adjustable or fixed? shelves spans can be short or long depending on how you build them. There just so many possibilities on something like this.

For instance on material usage. If I want the best use of plywood the shelves will finish out at 12’’ inch with after edge banding with solid wood, that way you get 4 rips out of a sheet. 3 rips per sheet you can have 16’’ shelves etc.

Which brings up the question, what you going to make it out of.

-- Alaskan's for Global warming!

Twenty inches deep on the bottoms and 12 on the top would look pretty good. Consider what material you will be using and see how you can maximize usage with as little waste as possible.

+1 What Alaskaguy said.
For cabinet uppers, 11 1/4 is good. Add a face frame that is 3/4 inch thick and you have a 12 inch cabinet. That makes it easy to rip sheet goods and have very little waste.

-- Handcrafted by Mike Henderson - Channelview, Texas

Twenty inches deep on the bottoms and 12 on the top would look pretty good. Consider what material you will be using and see how you can maximize usage with as little waste as possible.

+1 What Alaskaguy said. For cabinet uppers, 11 1/4 is good. Add a face frame that is 3/4 inch thick and you have a 12 inch cabinet. That makes it easy to rip sheet goods and have very little waste.

- MT_Stringer

Might as well cut rips 11 7/8” and get the most out of it.

I try to keep openings under 32 so you get 3 pieces out of the sheet,
plus the span is about as long as you would want anyway.

Making the TV sized for the biggest you may get is good.
Most of my clients mount the TV’s on an articulating arm and bring them out flush with the face.
I make frames to fit the TV and when they upgrade to a larger TV all you have to do is re-cut the frame to fit.

I would prefer 22” for the base if you have the room.

Doug, I think you are right on with your sizes!!

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

Thanks for the replies guys! I think i’m going to go with 11 7/8” cut shelves (with 3/4 face frame) and then 20-22” deep base cabinets

A few questions I forgot to ask….what is the typically height of the base cabinets? Same as kitchen cabinets? We decided we do not want a toe kick. Also, what is probably the widest doors I’d want to make on it? My wall spans 16’ across. Planning on adding drawers and doors so want things to look proportional..

-- Hey you dang woodchucks, quit chucking my wood!!!!