Bouncy room?

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#1

Originally Posted By: jmichalski
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150 year old house. Many of the floor borads (random width pine, tongue and groove) are loose and have some bounce to them.


The effect is alarmingly amplified on the second floor where the client (a 105 pound woman) jumped up and down a little and the whole room shook. And I mean a LOT!. There is also a noticable sag in the center of the room.

I am no structural expert, but it seems as if the floor joists are sagging (possibly undersized?) in the center. Am I overlooking any other possible causes for these problems?

I'd like to be sure before I tell this woman that if she wants to fix it she probably has to tke up her floor boards...

If it helps any, a peak in the very small crawlspace revealed that the rafters and joists were 2x4 members (actually a little thicker than 2"). I can't imagine the floor joists are 2x4, but I guess anything is possible.

#2

Originally Posted By: rlind
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Joseph,


I believe that the maximum allowable deflection for floors is 1/360 of its span. In large spans, this is a noticeable deflection. Of course, noticeable sags mid-span probably tell you there is a reportable problem...

Hope this helps!

#3

Originally Posted By: roconnor
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jmichalski wrote:
... the whole room shook. And I mean a LOT!. There is also a noticable sag in the center of the room.

Sounds like a potential problem that should be looked at closer.

Just my opinion and 2-nickels ... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong
#4

Originally Posted By: jmichalski
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I agree that it probably needs closer scrutiny to dtermine the exact cause, but I was attempting to determine if the floor HAD to come up or not (i.e. somehow an unsafe or structural concern.)


I assume that the deflection is not appropriate (probably WAY more than the 1/2 inch that would be allowable in a 15 foot span (the dip is really noticable). The "give" in the floor just adds to the concerns.

I appreciate the input.

#5

Originally Posted By: Brian A. Goodman
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[quote=“jmichalski”]


The effect is alarmingly amplified on the second floor where the client (a 105 pound woman) jumped up and down a little and the whole room shook. And I mean a LOT!. There is also a noticable sag in the center of the room.

I'm with Robert, that doesn't sound good at all. What's going to happen if / when the 105 lb. woman puts a bunch of furniture up there? What if it's big, heavy stuff too? There's serious disaster potential there. Recommend a structural engineer, don't try to provide the answers yourself.

If it helps any, a peak in the very small crawlspace revealed that the rafters and joists were 2x4 members (actually a little thicker than 2"). I can't imagine the floor joists are 2x4, but I guess anything is possible.

A lot of the old houses around here have those rough-cut 2 x 4 pine framing members, but the floor joists are normally a little bigger. Don't speculate...state the facts and your observations, lay out the potential for problems IF the joists are indeed inadequate or failing, and recommend a structural professional to take the ball the rest of the way.

#6

Originally Posted By: dvalley
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Quote:
a peak in the very small crawlspace revealed that the rafters and joists were 2x4 members (actually a little thicker than 2"). I can't imagine the floor joists are 2x4, but I guess anything is possible.


Those are (what I call) real 2 X 4's. When 2 x 4?s started coming out they actually measured 2? thick by 4? wide. Today a standard 2 x 4 measures 1 ?? x 3 ??.

--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."
#7

Originally Posted By: ssmith3
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Growing up in New Hampshire there was a house in my little town that had a second floor that was on springs. YEs I said springs. It seems that in the good old days they would clear out the upstairs and have dances there. The idea was that the springs in the floor would enable you to dance longer with less fatigue.




Do a search for antique spring floors.

–
Scott Smith


Marinspection


Vice President NorCal NACHI Chapter


I graduated from collage. Now my life is all mixed up.
#8

Originally Posted By: phinsperger
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dvalley wrote:
Those are (what I call) real 2 X 4's.


I call them full dimensional 2x4 ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

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.


Paul Hinsperger
Hinsperger Inspection Services
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here !
#9

Originally Posted By: jmichalski
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Thanks for all the advice.


The room is already furnished, so the floor is carrying full weight right now (and thankfully it is not on springs!!) My report notes possible causes and remedies, but calls for evaluation by the SE.

My hesitation on the SE call is because there is no corresponding evidence of problems elsewhere - just this one floor. The ceiling below is pristine (despite this woman's best efforts to jump through it).

Shouldn't joist sag be observable as deflection in the ceiling below as well? Or at least cracking?

The whole thing was odd. Generally the older the house I have inspected, the more solidly it is built (unlike the new McMansions, which I'm pretty sure can be entered with little more than a utility knife.) There are, of course, age issues, but generally the structure has been solid. I guess there are gems of all ages.....

#10

Originally Posted By: dvalley
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Quote:
Shouldn't joist sag be observable as deflection in the ceiling below as well? Or at least cracking?


Not necessarily. Most ceilings are installed against the same floor joists but in your situation there must be a good size cavity from the floor joists to the ceiling structure itself.

--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."
#11

Originally Posted By: roconnor
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, and where there are indications of a potential significant problem call for further evaluation by an SE. Otherwise ya might end up with a bill for framing modifications that can get costly … icon_eek.gif . Keep us posted on how this one turns out.


Just my opinion and 2-nickels ...

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong