Timber embedded in wall

[JDLDIY]

Cutting a long story short here! When a timber beam/joists/s is embedded as part of the structure of a wall, with bricks resting on top and which then needs plastering over on both sides, how is this done? Can the plaster just be applied straight to the timber? I always thought that timber should have air around it to prevent rot. Maybe the timber needs treating first?

Thanks a lot

JD

 

[masona]

The floor joists end should be treated into the wall, if the end of the timber is rotted then you got to find out what causing it in the first place. The floor joists do not hold the structure of the wall.

 

[TexMex]

You don't generally need to plaster around the joists. There's usually a floor on top of them, and plasterboard (or a void) beneath them. Only the visible parts of the walls are plastered. If you remove your floor boards next to the wall, you will note the virgin bricks still there.

That's because the plasterer didn't get there untill he had a floor to stand on. Also, if you remove the plasterboard from the ceiling, you will find that there is no plaster above it. That's because the plasterer would have waited for the ceiling to be in place before plastering the walls (otherwise he'd only have to come back later to do the ceiling).

Where you have exposed beams, these were generally done a few centuries ago. In such times the "plaster" would have been a lime render, which does breath! These beams were also generally made from far superior wood to our current softwood joists. (Oak was quite common). They were, therefore, inherantly more resistant to rot.

 

[JDLDIY]

Thanks for the replies guys. I'd better put a bit of meat on the bones so to speak because I don't mean joists as used in the normal sense.

I live in an area where a lot of the housing stock was built in the 1960's to standards that would be cringed at today. This is the second house I have owned where upstairs walls are built off joists which weren't thick enough etc. In my last house I had quite a bit of structural work done and I am facing similar jobs in this house. One of the jobs done in the last house was to install steel beams at first floor level between the floors to support wall ends and then the first few courses of bricks were removed from the upstairs wall and replaced with a wooden beam, sitting underneath the wall. One end of the beam was sitting on the interior leaf of the outside wall and one end on the steel rsj. The beam was then plastered in so that you couldn't tell it was there. I wasn't there to see it done however and I am now facing a similar job, hence the question.

JD

 

[TexMex]

The method of using a I beam within the ceiling is not uncommon. My own living room has this arrangement, and it was built that way! Rather than attempting to build a wall plate into the wall, however, it would be simpler to use joist hangers at the wall end.

You still wouldn't need to plaster around the joists, as they would be between the plasterboard and upper level floor boards.

 

[JDLDIY]

The reason for this particular type of installation was due to the arrangement of the walls and flooring. In my particular situation now it would also be a viable solution, just wanted to know what the implications would be of putting the wood into the wall and covering it with plaster. Should the wood be treated specially etc..

JD

 

[TexMex]

I'm still having trouble getting my head around exactly what you are proposing. This is partly from your use of fairly vague terms. The "beams" that support the floor boards are called Joists. A wooden beam that supports the joists is called a Wallplate.

Now, if I'm reading you correctly, the project you propose would consist of:
A Metal beam (of an I type cross section) running across the room.
A wall plate (running parallel to this beam), built into the inner skin of a cavity wall.
Joists supported at one end on the bottom lip of the metal beam and at the other by the wall plate.

This would involve removing a course (layer) of brickwork from the inner skin of an external wall, and putting a wooden wall plate in it's place. If this is what you're planning, I'd say the finishing touches would be the last of your worries. How are you going to support the wall above the wall plate while removing the bricks?

Instead of the wall plate, it would be a lot easier to use metal joist hangers. Such as these.

(Credit to MurraySmudge for finding this jpg for another thread)

 

[Bradleybuild]

wood in the wall, use tannalised
you want to plaster it
use expanding metal lath or better still ribbed EML
and put a base coat of sand and cement or hardwall then skim as per yer normal walls
cheers

 

[JDLDIY]

Many thanks but I'm not sure how you found this thread as it's well old!