Span of a single piece of timber

[RossCrooks]

Hi there, I have used these forums for a while but never registered. I am however at a loss to find the answer to this.

I have a wall in my living room that I wish to take down. The wall is supporting the upper section of my house.

- The beam spans 4m
- I have calculated the load on this beam to be 800 kg.
- It is a timer beam made from doubled up 2x8's.
- That is supported by doubled up 2x4's and a framing timber wall.
- This all rest on the floor joists.
- I will be leaving the 2x8's and the 2x4's that hold it up and either sides, but removing the middle section to open it up.

My question is, how much weight can these doubled up 2x8's take with acceptable deflection? I can't find any information regarding a single beam, or, what I would need to reinforce it (Steel probably?)

Please see attacyhed annotated photograph. Many thanks for any help!

 

[ree]

FWIW:

what you need is experienced eyes on site.

The pic shows a number of possible difficulties not least that your lintelled partition was most probably not erected with Regs. & BCO's approval.

 

[^woody^]

That stud partition does not appear to be load bearing, so the beam should have been designed to take whatever load is above it.

This 800kg of load, what exactly is it and is it uniform across the whole beam?

 

[tony1851]

You say 800kg dead load: have you included for live load as well?

 

[RossCrooks]

Sorry, the 800 kg is dead load. I am unsure of the live load. I got the 800 kg by adding together the weights of plasterboard, plaster, furniture, joist weights, clothing, plywood and laminate flooring, then divided this by two as all joists run to an outside supporting wall.

The wall Def looks like it hasn't been approved. The work has been poorly done and doesn't look like part of the original construction.

Oh and the load is fairly uniform. The joists upstairs are covered with 1200x2400 plywood sheets.

 

[tony1851]

You seem to have worked out the dead load, but you have to add the live load as well. This is the weight of people,
furniture and things we put in rooms. Obviously it varies a lot, so there is a standard unit load required to be taken into
account, which is about 150 kg/m2.

 

[RossCrooks]

Thanks for your reply! I have spoken to other people regarding this (one knows a structural engineer) and he has suggested a steel beam replacing the timber.

 

[tony1851]

Thanks for your reply! I have spoken to other people regarding this (one knows a structural engineer) and he has suggested a steel beam replacing the timber.

........and doubtless he will give you a price for calculating the steel beam.

Why not take the wall out stud-by-stud and see what happens? That timber does look a hefty piece.

 

[RossCrooks]

Thankfully the guy is a friend of a friend. I might prop it up and lower it slightly. I'm worried the sagging might take weeks and months to occur though...