Is a subfloor required by modern building code?

Factual Questions
1

I watch a show called Rehab Addict. Nicole Curtis, a bubbly blonde lady that saves old houses on a shoe string budget. Lets just say lots of creatively inspired, jury-rigged work. :slight_smile:

I don’t understand how Nicole got this bathroom floor past the building inspectors. There’s no subfloor. Nothing keeping someone from falling through into the basement except some old pine boards she salvaged from the attic. She took up the old plywood subfloor and just nailed these old pine boards to the floor joists. Sanded, stained, poly. Looked nice, but theres little support there.

I can imagine someone sitting on the toilet and seeing light between the board cracks. It’ll be very noticeable when someone switches on the basement lights.

Isn’t a subfloor required by code? Especially over a basement? Thats a 8 foot drop.

2

I don’t have a clue, but I’ll hang around to find out.

3

IDK but I have seen such construction in upper floors of older homes, and yes you can see light coming up (or down) though the joints (edges?sides?).

If the boards are 2x4, or 2x6 or 2xwhatever I would think it would be strong enough, though a toilet overflowing water would be in the basement very quickly.

4

I’m just baffled why she didn’t put down plywood as a subfloor. It was a small powder room. One sheet of plywood would cover the floor.

I thought she was going to fall into the basement nailing those pine boards across the floor joists.

Some work she gets professionally done. It’s her DIY work that leaves me shaking my head.

5

Tongue and groove “car decking” is sometimes used as a floor without a subfloor.

6

bathrooms.

i thought Rehab Attic was about getting additional upper story living space.

7

Local codes will vary, but usually the floor strength requirements have to be met and that’s it. It’s quite common for timber frame and log cabin homes to use plank flooring with no subfloor. However a common exception would involve fire codes. Usually a double layer of sheetrock under a floor over a garage is required, and a subfloor might be a requirement there also. Earthquake, hurricane, and tornado zones might have more stringent requirements also.

8

It wasn’t tongue and groove?

Not all areas have building codes. Is she in the country?

9

He said the show was called Rehab Addict not Attic. And in a bathroom, I’d think you’d want a waterproof floor; vinyl, ceramic tile, etc.

10

This was a house in Minneapolis. Nicole rehabs old derelict homes there and in Detroit.

I didn’t see any notches or tongues on the boards. They were just wide, pine boards she salvaged from the attic. Probably 80 years old. That was a good idea. I was just surprised she didn’t install them over a sub floor.

After thinking about it. I’m pretty sure she’s stripped linoleum in other houses to the bare subfloor boards and refinished those old rough boards. She works on a very tight, shoestring budget.

Older homes used plain boards for a subfloor. Sometimes they are old growth pine and really look nice after sanding and finishing.

11

Old subfloors were typically 1x4 shiplap, tongue and groove, or even just dimensional lumber; usually laid diagonally. Its plenty strong, though I have seen some homes where the lumber was installed ‘green’ and had shrunk considerably. Tongue and groove is much stronger obviously than shiplap or just dimensional lumber.

Around here it’s often old growth Doug Fir which is a very strong wood and looks beautiful finished like a hardwood floor. Old pine as described, (which might be even closer to 1" than 3/4 if its old enough), installed this way would probably be OK, but it would be a much better idea to put a plywood or OSB subfloor under it first. Transition to adjacent flooring may have been an issue.

All that said, I bet this isn’t being inspected. Old houses are not built to modern code obviously but renovations in most jurisdictions need to be done to current code. Simple jobs can turn into nightmares. I love old houses but they are scary to work on.