Why is there sand and cement half way up my wall?

[Walnuts]

Afternoon.

I’ve got blown gypsum plaster essentially in a straight line about 4 foot up across the whole of a small internal brick wall. Started hacking it off and realised underneath I’ve got sand and cement up to where the plaster is blown, and a very thick layer of lime above. They’ve plastered over the whole lot with gypsum so I’m assuming the difference in expansion between the lime and sand and cement has caused the gypsum to blow.

The lime is as uneven as anything and you just have to look at it funny for it to fall off so I’m taking the whole lot off and boarding as there’s no damp. The sand and cement is a pain in the backside to get off.

Any ideas why there would be sand and cement only part way up the wall? Knowing the rest of this house it’s probably because the previous owners were cheap but just wondering if there’s a reason I don’t know about - maybe damp proofing? But like I said we don’t seem to have any damp issues.

I take it it’s better to get the whole lot back to brick and I can’t board just where the lime was, leave the sand and cement and SBR the lot before skimming?

 

[JohnD]

Probably an attempt to cover up damp at the foot of the wall.

If you are lucky, the actual cause of damp, such as an overflowing gutter, a broken drain, leaking pipe or rain pooling against the wall, has been repaired.

 

[Notch7]

Any ideas why there would be sand and cement only part way up the wall?

my guess is the lower part of the wall was damp so somebody stripped off the lower part and did it in sand and cement maybe with SBR to make a waterproof coating

whats happened is its forced the damp to travel further

 

[cdbe]

It was/is fairly standard to (sand/cement/waterproofer) render the bottom meter when installing a dpc. The old plaster on top has probably just blown with age. Make it up with whatever you're best at eg board or render and skim the lot.

 

[JohnD]

It was/is fairly standard to (sand/cement/waterproofer) render the bottom meter when installing a dpc.

When injecting a chemical in the forlorn hope that it will cure the actual defect that is the source of water

 

[23vc]

The render half way up is pretty common for damp treatment. Seen it done post-flood in affected streets, as well as other causes