I've recently purchased home office furniture and placed it on the second floor of my one
family, sidehall colonial, built circa 1983 in New Jersey. The furniture is solid wood and very heavy (approximately
1100+ lbs) in a 20' by 20' room. My wife is very concerned that the floor may give way under the weight of the furniture. Is there any
validity to this concern? Are there any standards that suggest what the minimum/maximum weight limits are for
the second floor? I don't have the blueprints and do not know who the builder was.
Thanks in advance for your response...

Loading is not calculated by the total weight of an object unless all of the weight was concentrated in one spot. The weight of household items is dispersed over the whole area of the individual piece. Without knowing the size of the floor joists and if there is a bearing wall underneath, nobody can give you an accurate loading for your floor.

Thank you for your response Dr. Home. Can you elaborate further on how I can get the information related to the size of the floor joists?

As far as a bearing wall, I believe that there is one about 20' into the house on the first floor, but it does not go across completely. I assume that there probably is some sort of support beam spanning the remainder of the space. Is that likely?

If your house was built to meet or exceed your local building codes, the 2nd floor should have been designed to withstand around 25lbs per square foot of live load (people, furniture etc). Theoretically, (20x20)25=10,000 lbs. I seriously doubt that you have a problem. Imagine how much weight a kingsize waterbed must weigh. You don't have one of those in there too do you?

Theoretically, everything Kansasz has said is
true (you could even place a waterbed in the room if everything was built properly). However, I have seen alot of strange and scary building practices, which is why I am always leery of giving structural advice without always having all of the details. Given a 20 foot span, any good contractor would not go below a 2x8 joist using pine. If it was anything less you should be able to feel a springy sensation when bouncing up and down on the floor or a strong vibration when people walk across the uncarpeted floor.

Actually Dr. a 2x8 spf @ 16" o.c. is only good for about 11 feet. With a 20 foot span his floor would seem springy with 2x12's. Any good contractor would have a microlam or some steel under there about mid-span as jb suggests. Jb, Call your local building codes department and ask them if they inspected your house. In my experience they keep pretty good records. They would not have specific records on how your house was put together but they would at least be able to tell you if it passed a framing inspection. If it did and your floors are not overly springy I think I would not lose any sleep over the issue.

Kansaz,

You are correct on the span. I was foolishly assuming that there had to be a bearing wall or support beam under the floor joists, thus cutting the span somewhere at midpoint. Yes I know the definition of ass u me, sometimes I forget to remember it.