Dipping Floor

[gelpack]

I have jsut bought a house and have a potential issue with the floor in one upstairs bedroom.

The main room is at the front of the house and the small bedroom also. The joists run across the width of the house ( left to right ). In the main bedroom there is a dip on one side of about 15mm which spans about four feet at its worst on one side ( the small room side ). However, the floor on the other side of the partition wall in the small room looks relatively ok.

I cant understand how this could possibly be. I havent taken up the floor yet, but was wondering if there are any gems of wisom anyone could share. If the joist was mispositioned, then I cant understand how it could dip one side of the partition and not the other ?

 

[JohnD]

you say the dip is four feet

four feet one way by what the other way?

which dimension is in line with the joists?

Is it a chipboard floor?

 

[gelpack]

Yes, it is a chipboard floor.

The width of the dip is 4 feet and runs across the joists

The depth of the dip at its worst in the centre of the 4 feet span is 15mm


Small bedroom side.
J J J J J
========== Partition Wall==========

|--------------><Dip centre -----------|
J J J J J
J J J J J ( Main Bedroom Side )

 

[JohnD]

I wanted to know the length and width of the dip

So it is 4 feet long and 15mm deep, but how wide is it?

Of if you prefer to say it is 4 feet wide, how long is it?

 

[gelpack]

Difficult to say to be honest, I think around three feet or so, but my level is not long enough to say exactly

 

[JohnD]

so it should be supported by about three joists. I think you are going to have to pull it up and have a look. Use a TCT circular saw if you have one, set to just under 18mm (to avoid pipes and cables) and you will be able to break out the dipping section. Cut a very straight line to make it easier to put in the new piece. If you can make it 1220 from the next joint it may be easiest. You will probably need some 50mm x50mm or bigger noggins to support the cut edges on reassembly.

If the dip was 4 foot wide parallel to joists, then I would think that the chipboard had an unsupported short edge that had given way when the T&G broke. This is very common with chipboard, which is a dreadful flooring material.

 

[gelpack]

Im going to rip up a section tonight, so Ill have a look. Not sure what and where the tongue and groove you are refering to is, but I iwll take a look, I just hope I dont find anything too awfull....


Thanks for you help and I will let you know what I find.

Cheers

 

[JohnD]

chipboard flooring is made in sheets 2440x1220mm (and sometimes 1220x610 which are easier to carry)

each edge has either a tongue or a groove machined into it. When they are laid these interlock and help keep each other rigid.

Short sides which are not laid over a joist are to some extent supported by the tongue. But it often breaks off, and then the panel is unsupported and goes springy or cracks and dips down. This is very common with chipboard which is a dreadful material for a floor. If repairing it I recommend 18mm WBP ply. You can get this for flooring, with T&Gs that fit into existing chipboard panels.

 

[gelpack]

I see your thinking, when I took the carpet up last night, what I found was on closer inspection that the dip actually goes under the partition wall as well although its not as pronounced on the other side of the partition.

It lookas as if the joist has bowed possibly. This could have been due to something heavey being stored on it during construction, such as roof tiles etc.

Due to the extreme heat and the fact thatI could not have done anything anyway last night I havent taken the flooring up yet.

However, on the ceiling below there is evidence of the dip as well although there are no decorative issues or cracks anywhere.

There are also decorative beams which are scrweed to the joists on the underside of the ceiling and the one where the dip is stands proud at the edge by about 8mm. I scrwed this back in with a strong screw and found that this must have been like this for a very long time as the room doesent look to have been decorated in my oponion for at least seven or eight years. So, in essence I dont think anythings moving, its just a bit of a pain.

If I think about my options.

1.) If the joist is simply bowed or out of shape, then some remedial action would be required to level the floor, perhaps sistering of the joists, or even something as simple and cheap as leveling compound maybe.

2.) If the joist is broken or cracked, then this is a whole different story, I dont think its feasable to have to bring down two ceilings and knock a hole in the side of the house to fit a new joist.

What to you think ?

2.)