help - loose breeze block on internal non-supporting wall

Hi all,

Am having small bedroom replastered at the weekend.

There were some areas of dodgy render that I am removing ready for the plasterer to apply bonding over before skimming.

I have found a very loose breeze block at the base of an internal non supporting wall. The wall is only about 1 foot wide and is situated around the door frame. It sits on floorboards on joists and extends up to the ceiling. The house is 50's ex-council.





As you can see there is a hefty crack. It goes right through the block and I can wobble the block about 2 to 3mm of wobble. I don't want to pull it out incase the internal wall collapses. Do I repair with mending plates and pack some mortar in? Or do I call off the plasterer and call a builder in?

Many thanks

It’s not a big deal & your wall won’t collapse; I’ve fixed a lot worse than that & it shouldn’t be a problem. Talk to your plasterer first but what I do is: remove the plaster back to block, 150mm either side of the cracks, rake out the joints & get some mortar in there. Fix some strips of stainless steel reinforcing mesh over the joint/cracks so it overlaps at least 75mm either side. Apply Bonding or a sand/cement render over this, out to the surrounding wall level. Prior to skimming the whole wall, I also apply a couple of strips of reinforcing tape where the 2 meet for good measure.

I assume he’s just bonding the damaged bits (skirting, holes etc) prior to skimming & not bonding the whole wall?

Hi Richard, many thanks for your reply.

Yes the walls are rendered (as are all the walls in the house) and apart from damaged sections the walls are not being re-bonded.

I will see what plasterer says on weekend then. In the meantime I may try to repair with some mesh. My concern was that if this brick is loose, then all bricks above are going to drop too. There is already another crack in the render about a foot higher, going horizontally across the wall. However I can detect no wobble in this section of the brick.

The door frame could be the only thing holding this wall together?

All minor stuff: it's dropped as it's not bonded into the cross wall and, over the years, the timber floor off which it's built has shrunk as it's dried out. Add vibration from the door being opened and closed and this is the result. The next block up is bonded into the cross wall, hence it and the wall above it still sitting there quite happily.

If the block is loose and left like that, then it could still wibble after being re-plastered and re-crack the finishes. As such, re-mortar the joints before doing any plastering; might need a bit of slate rammed in there top and bottom, just to make sure.

I see Shytalkz pre-empted me! Re the crack higher up the wall; I would also cut the plaster back to block to have a look at that as well. It’s likely to follow the mortar line but if it’s just in the plaster/render, re-fill & skim over. If, however the mortar or even the block is cracked, cut back & reinforce with mesh as before. In fact, I would investigate any other cracks that look more than skin deep; if there are corresponding cracks in the underlying blocks/mortar they will probably reappear in the new skim if you leave them as they are. If it gets to the stage where you have more cracks than wall, sometimes the easiest option is to overboard the whole wall.

Hi,

I have repaired the block. It actually came out all the way when I tried to knock the render off so I cleaned it up, knocked all the mortar off it, cleaned up the hole and mortared it back in, packing the mortar in as tight as I could on the top and sides. The plasterer hopefully can bond over this now and get a level finish with the remaining wall.

I was surprised to learn that it was only 2" thick. Its like a very thin internal breeze block, made of a very dark blackish substance a bit like the bubbles in an aero chocolate bar. Its also square, not oblong like most breeze blocks / thermal blocks you see in the shops. At one end its got a protrusion sort of like a tongue on floorboards. Presumably if I had a row of these they would all slot together with a tongue and groove like arrangement.

Can anyone shed any light on the material / construction. The house is 50's ex council, but so was my last house and those upstairs internal walls were stud partitions. There is another much bigger wall (11ft long) separating the bedroom with another bedroom that is made of the same blockwork. This too sits on top of the floorboards and also has some cracks near the bottom. I have managed to chase in 2 25mm socket boxes but am amazed (lucky!) that I didn't break through the other side given the thickness of the block!

In the ideal world I could have knocked down all the walls (3 in total separating bedrooms upstairs) made of this material and replaced with 4" stud wall. Should I have done this do you think? Too late now really.

Cheers

It's not unusual construction for the time, just the old clinker blocks. Must have made it interesting when they were laying them though...I'll huff and I'll puff, but not a lot and...oops!

jesus christ almighty throw some muck on it , then plaster it