I want to purshase a 1920 cracker house that was moved to its current location in 1995. There is not a subfloor - as in where a knot has fallen through you can see the dirt under the house. There are some soft spots in the hardwoods and a friend recommended having a subfloor installed to provide support and deal with humidity issues by then insulating under the sub floor (the house is in Florida). The house is about 2-3 feet off the ground. Is this even possible? Very $$$?

Also three of the support beams are original and are showing some signs of decay in spots, can you replace these one by one or will the house need to be lifted? My woodworking friend wants the antique beams after I take them out but is not qualified to replace them. The kitchen floor slants some but I assume that can be fixed with the support beam is replaced.

The floors have no finish on them and the house is otherwise very nicey restored (all new plumbing, electric and a tin roof within 10 years). Original brick fireplace and mantle, as well as wonderful wood walls and ceilings (some cedar) so I am excited about potential ownership but don't want to buy a moneypit or be sitting in my clawfoot bathtub and fall through the floor !!

Thank you sooooo much for your advice and comments!!!!!!

What you are talking about is primarily structural. You should consult a general contractor or construction engineer. I hope you are having a professional home inspection before you make a purchase offer. Structural repairs are expensive and should only be performed by experienced and licensed contractors. And I am sure you have a sub floor of sorts. I don't know what it is; probably a solid board floor.

Some of the homes built here that were part of the original settlement some 150 to 200 years ago and even those that are only built up into the 40's have no subfloors. The flooring is right to the joists. Shorts are not nailed into anything and most are joist on 1 foot centers, some on 16" centers. Homes built in the 50' and 60's before plywood, had 1x slats on 45º. Usually Cypress.

I would consider that wood installed over the joists to be a sub floor that never had a finished floor installed. Example: We know in New England, many of those early colonials and saltbox homes used rough hewn timbers as joists and just face nailed thick pine planks over them. Those floors weren't T&G and they would chink the gaps with rope and tar if they wanted; similar to boat decks. The more affluent would cover those wood floors with rugs from China, India and France. Later on, in the Victorian era where ornate woodworking was admired, they overlaid these same subfloors with parquetry and fancy strip. At that time, the industrial revolution was in full swing and steam power was utilized in manufacturing , making the milling of flooring, and many other products, much easier. So in the last part of the 19th century, T&G flooring and parquetry was commonly available. Many homes here on the west coast used 3&1/2" x 3/4" douglas fir flooring as subfloors. These were T&G nailed directly over the floor joists. They could be used as a finished floor by oiling, waxing, painting, etc. or in better homes and buildings, they were covered with a real floor covering. Hardwood, carpet, linoleum, tile, etc. Other subfloors were non T&G planks, 6" to 12" in width, and were installed at either a 45 or 90 degress to the joists and were again, face nailed. These definitely needed floor covering as they were so uneven and of a low grade of wood. Plywood became available in the 1930's but was not used much in residential until the 1950's and 1960's. It's quite possible that the floor you have was meant to be a combination subfloor and finished floor. The only HARDWOOD I've seen that was NOT installed over a wood subfloor was installed over sleepers (screeds) which were over concrete, which, in this case, would be considered the subfloor. I have never heard of or seen hardwood flooring laid directly over floor joists. However, no reason why it could not have been done. And just because I'm not aware of it doesn't mean someone did not do it.

The floors here over joists are 33/32 2¼ T&G oak, some have blocking between joist at the perimeter, and have borders.

Wow, can you imagine installing a nailed down oak floor over just the joists? I wonder how many guys missed their footing and slipped into the crawl space? Just like nailing over sleepers I suppose, which I've done. But there was a concrete slab a couple of inches below them.

Thanks for all the reply posts. I am meeting with a contractor Wednesday morning to get professional advice. I'll let you all know what he has to say about how the floors and supports are installed. I really hope it is not cost prohibitive as I really want this house. The wood on the walls is gorgeous!

Thanks again

... and there is no subfloor. In fact, he after spending about 40 minutes under the house (I went with him, very interesting) when checking the floors from the top side he turned and looked at me and said "I hope you like bugs".

Turns out the support beams (very good pinewood tree trunks hand planed from the 1920s) are in good shape and should last many more years. The floors though squeaky (and a bit flexible when jumped on) are sturdy and need only a couple of beams reinforced. BUT one whole row of cinderblock support columns have sunk. Luckily they sank evenly but to really fix very expensive. Also the sinking is causing the lengthwise walls to not be straigh - as in house leaning a bit towards the side that has sunk. Maybe they are done sinking, maybe not!

Not sure what I'm going to do....but definitely am not paying $104,900 for a sinking, leaning 720 sq ft house no matter how much character (did I mention the original fireplace and mantle?)

Thanks for your help. Now have to decide if they accept my low offer whether I try to fix the leaning part of the house or just tear it down, put in more support, and build brand new kitchen on other side of house in denser soil!