Cracking wall

[noseall]

That's the only way I've ever seen it done.

Where? Photos? The only way.

I guess you ain't seen much done then.

I can push a screw driver into hemlites. (cinder block, ash block)

Try and push a piece of 2" timber into a block and see how far you get.

All 3.5n blocks will crack if you kick them.

Joe, the one thing you are forgetting is that most internal load bearing structures are built from blocks that are full of air and are 'soft' by comparison. These are preferred and recommended by all architects, all designers and all at b.c.

Where you get the idea that the internal walls of buildings are built form dense 7n type concrete block is total and utter horlics.

Some point load locations are either borne by padstones or dense blocks or bricks.

 

[joe-90]

Some point load locations are either borne by padstones or dense blocks or bricks.

So they aint so hot then?

 

[noseall]

Some point load locations are either borne by padstones or dense blocks or bricks.

So they aint so hot then?

No they are not. The reasons for using blocks that are full of air is for their thermal performance. Their load bearing capacity is adequate for their purpose.

Point loading and impact lods are borne by denser materials but the weight will still be on the aerated block. A joist can sit directly onto aerated blocks, no probs.

These blocks tend to crack because of thermal movement or shrinkage and not because of loads.

 

[duffsparky]

Hi Gents,

As much as I like a good debate or even a slanging match, this thread seems to be getting away from the original topic.

I wonder if Joe 90 is on a wind-up. I'm a sparks and one of the electrical forums I go on to, has all but collapsed due to wind-up merchants.

Anyway back to the original topic, do I have a problem with cracked motar lines and split Thermolite type blocks? If so, what's the best course of action.

Kind regards.

 

[noseall]

Sorry Duff. Yes joe is a w.u.m. and has been reprimanded by the mod's in the past.

Is the wall an inner partition wall or is it the inner leaf of the cavity?

Some partition block walls are only 75mm thick and do not take much stick. Expanded metal with a bonding coat will be a good repair.

Dabbing plasterboards (with plenty of dab) to a fractured partition block wall can stiffen it considerably. Only good if you have the tolerance and a wall free of any plaster.

 

[joe-90]

As the OP has found out, Thermalite block is a poor structural component that many engineer/architects never use in a load bearing situation.

His best course of action now is to rake out some of the mortar courses and slip stainless steel rod into them as in a Helifix repair. Costs peanuts works like Viagra, and as for plasterboard? He's just having you on.

 

[noseall]

and as for plasterboard? He's just having you on.

Fixing boards to a surface adds stiffening to that surface, whether it be plasterboards to a stud or masonry wall or ply sheets to a floor.

If you were to dab plasterboards either side of a damaged block partition wall the entire wall would be stiffened and strengthened considerably.

Your grasp of structural engineering joey is dismal.

 

[joe-90]

That's a bodge. Pure and simple. Structural engineering with a bit of plasterboard? Just knock the silly wall down and rebuild it.

 

[mater]

they are used to achieve the correct u-value in houses

 

[Ionkontrol]

That's a bodge. Pure and simple. Structural engineering with a bit of plasterboard? Just knock the silly wall down and rebuild it.

I'm totally with Joe on this one, wind up merchant or not.

Sounds like classic MINIMUM spec build quality, just like any of the flats/houses I"ve seen built recently.

Next thing people will be saying is that metal stud partition walls are great.

7NM+ for all internal walls FTW.

 

[Shytalkz]

And strangely you can get 7MN Thermalite. Even stronger ones too.

They are thermally more efficient than concrete and using the stronger ones is less likely to result in shrinkage cracking.

The point being that Guiseppe, when saying that all structural walls are built out of concrete blocks was, not unusually, spouting shi'ite.

 

[duffsparky]

Is the wall an inner partition wall or is it the inner leaf of the cavity?

It's the inner leaf of a cavity wall.

I wondered about raking the cracked mortar out, just shy of going right through, and then pushing in new mortar.Then rake out the cracks in the blocks to about 12mm wide and filling those with new mortar? Kind of rebuild the wall area without actually pulling it down first, obviously doing small areas at a time, or perhaps vertical lines first followed by the horizontal ones and finally the splits in the blocks.

Another option that's been suggested to me is to gently remove all the plaster and render from the affected area, then fix expanded metal sheet laths over it and finally replaster with bonding.

Regards.

 

[joe-90]

And strangely you can get 7MN Thermalite. Even stronger ones too.

They are thermally more efficient than concrete and using the stronger ones is less likely to result in shrinkage cracking.

The point being that Guiseppe, when saying that all structural walls are built out of concrete blocks was, not unusually, spouting shi'ite.

The point I was making is that the material used in the OPs house was unsuitable - hence his post in the first instance. Do you specify materials known to crack under very little stress?

 

[noseall]

Is the wall an inner partition wall or is it the inner leaf of the cavity?

It's the inner leaf of a cavity wall.

I wondered about raking the cracked mortar out, just shy of going right through, and then pushing in new mortar.Then rake out the cracks in the blocks to about 12mm wide and filling those with new mortar? Kind of rebuild the wall area without actually pulling it down first, obviously doing small areas at a time, or perhaps vertical lines first followed by the horizontal ones and finally the splits in the blocks.

Another option that's been suggested to me is to gently remove all the plaster and render from the affected area, then fix expanded metal sheet laths over it and finally replaster with bonding.

Regards.

If you start taking a hammer to it now, the chances are that you will end up with a re-built section of wall that is only moderately stronger (if any)than the fractured one you have already. You are best repairing as you have described.

 

[Shytalkz]

The point I was making is that the material used in the OPs house was unsuitable - hence his post in the first instance. Do you specify materials known to crack under very little stress?

There have been problems with aac type blocks in the past boom times, due to inadequate curing. And they need movement joints at fairly close centres and/or careful detailing.

You seem to think that they are too weak. They are not, they are manufactured to a number of design strengths. But they do suffer from thermal shrinkage. Which is not the same thing: it is strain that causes the cracking, not stress.