Supporting Pillar

[Blackthumb]

Untitled

• Blackthumb
• 27 Sep 2010
• 1

Untitled

• Blackthumb
• 27 Sep 2010
• 1

Hi,
The first floor bathroom of my 1910 house overhangs the porch and is supported by a large wooden pillar. The bottom of this disappears into a rendered 'lump' sitting on the extended doorstep, see photos. Although the pillar itself seems to be sound I was alarmed to discover a large horizontal hole at the bottom of this render. Large enough to get my finger into. So, armed with some stiff mortar and a long skewer I proceeded to rake out the loose material from the gap, which appeared to be just a sort of earthy sand. And it just kept coming out, I could waggle the skewer several inches in every direction. Eventually common sense dictated that I stopped, and rapidly shoved a load of mortar into the gap, tamping it well in.
So, my question is, does anyone have knowledge of how these pillars were constructed? Does the wooden post go right through to the bottom, and presumably rot if the render/pointing fails, or is it supported on bricks or concrete higher up in the rendered lump, in which case my bit of repair work might be all that was required?
Any comments gratefully received, I'm reluctant to use the bath now, which is directly over the pillar!

 

[Static]

Hard to tell from the tiny photo but chances are the timber post sits on a concrete footing just below ground and the render is splash protection for the timber.. if you havent been maintaining the render then the timber will eventually rot away..

Best course of action would be to chip off the render around the post and see what the extent of the damage is.. maybe put in a couple of props while you do this..
In the end worst case is the bottom couple of hundred millimetres are shot and need to be replaced.. either by some new timber of a concrete plinth..

 

[Blackthumb]

Thanks for that Static.
I've never done a job that required serious propping so think I might call in a professional to take a look. Would a general builder be able to do this sort of work or should I get a structural engineer to look at it? I'm having a new bathroom put in and wouldn't want it to end up in the front yard!

 

[Static]

Would have thought a half decent builder should be able to easily sort it.. only get in an SE if they come across anything wierd..

 

[mnb]

With respect to other posters:

!. I suspect that the post goes all the way down to the recessed porch sub-floor, the lump is merely a sand and cement render/en-casement.

2. Prop the porch corner with 2 no Acrows and a plate across the top.

3. lay a level on the bathroom floor and the bath tub and against the external porch ceiling - is the corner sloping out of level?

4. Are any obvious cracks or deformities present inside or out? Check door and window head lintels for level.

5. The post is presumably rotted out and req's replacing - various options are available, but first establish whats what. Leave the post alone.

6. Your pic's wont expand !

7. Which way are your joists running in the bathroom.

 

[Blackthumb]

Well I've checked the bathroom for level and it seems perfectly OK. No cracks anywhere. The joists run from front to back. Reckon I'll hire a couple of acrows and investigate inside the render.
Any tips on how hard to screw them up? Until I hear splintering sounds?
Thanks all for your advice.

 

[mnb]

I would imagine that a similar difficulty has occurred with a neighbour, ask around.

The post seems to be 8x8? 6x6? A timber yard could advise on a suitable replacement. Or google around for a steel post.

Your Acrows must be on firm footings and merely require to be firmly screwed up and then, say, quarter turn tighter. Remember to plate across with an off-cut of 2x something. Everything tight and plumb. No splintering sounds.

The joists are probably cantilevered out and taking most of the weight.

Do the above and then get back to people on here.

Keep vehicles away from corner.

 

[mnb]

I've just noticed the decorative pelmets - front and return . They will have to be removed, the plate will pass thro their present positions and the Acrows must be under the rim joists.

 

[geraint]

With respect to other posters:

!. I suspect that the post goes all the way down to the recessed porch sub-floor, the lump is merely a sand and cement render/en-casement.

2. Prop the porch corner with 2 no Acrows and a plate across the top.

3. lay a level on the bathroom floor and the bath tub and against the external porch ceiling - is the corner sloping out of level?

4. Are any obvious cracks or deformities present inside or out? Check door and window head lintels for level.

5. The post is presumably rotted out and req's replacing - various options are available, but first establish whats what. Leave the post alone.

6. Your pic's wont expand !

7. Which way are your joists running in the bathroom.

i would suggest that the post sits on the obelisk. i doubt whether a render would survive ten hours around a timber post....

prop. cut out the rotten part of the post and scarf in a new piece.... job done....

 

[^woody^]

cut out the rotten part of the post and scarf in a new piece.... job done....

Can't see much with those microscopic images, but the OP said that the problem was with the bottom section of concrete not the timber post

I can't imagine why that lump would be solid concrete, and would have thought it be a brick pier which was rendered.

The OP should investigate that stump by trying to knock off some render to see if it really is a problem with the inner section or just defective render. He could do this without propping the joists up

 

[mnb]

Just noticed that Static had already spotted and suggested what i repeated. Sorry for that.

As for Geraint's suggestion: are you seriously suggesting that the point load of the house corner be suspended on a remedial joint in an already aged and damaged timber post? And given that a true scarf joint is an angled joint then the weight would be on the fixings not even on the post.

We dont know the condition, the materials or the construction of the situation so caution is called for.

Lack of knowledge is no excuse for bluster: render is used on millions of structures here, in the USA and Australia - posts on site are typically wrapped in 15ib felt and chicken wire and then rendered.