Plaster for patching

FreeBear

My first big wall. Chases and missing lumps from where skirting & picture rail removed filled with bonding coat. A base coat to level out the original "rustic" plaster, followed by two skim coats. Not looking forward to doing the arched alcove. Might end up using Fill & Finish for that...

danrv

Managed to get much smoother edges on this patch. Does depend on how even the surrounding wall is.


I find cleaning the tools after can be a long process as the plaster starts to dry on them. Also figuring out what to do with any leftover plaster but I do mix small quantities to avoid this.
I'm using three buckets - plaster mixing, water top up and cleaning water. 

FreeBear

danrv said:

Managed to get much smoother edges on this patch. Does depend on how even the surrounding wall is.

I find cleaning the tools after can be a long process as the plaster starts to dry on them. Also figuring out what to do with any leftover plaster but I do mix small quantities to avoid this.
I'm using three buckets - plaster mixing, water top up and cleaning water. 

Clean the tools as you go, and don't leave the plaster to go off. So mix your plaster, clean the mixer. Slap on the first coat, and clean the trowel & hawk. Flatten off, and clean the Speedskim. Clean out the mixing bucket and have a quick coffee. Mix the second coat, clean the mixer. Slap on the plaster, clean trowel & hawk. Flatten off and clean the Speedskim. Clean out the mixing bucket, tidy up a bit, and have another coffee. Spray some water over the fresh plaster, and hit it with the finishing trowel. Clean the trowel. Wait a bit, and hit the plaster again with the finishing trowel. At the join with old & new plaster, work the plaster a bit with a wet 6" paintbrush and feather it in. Use the (clean) finishing trowel to smooth over the join, and give the rest of the wall a final polish. Clean the trowel, floor, and any other mess.

Any leftover plaster should be disposed of responsibly at the local tip - You may get charged for DIY waste. Just don't tip it, or the dirty water, down the drain. The plaster will clog up the drain pipes and will cost a fortune to dig up & replace. Little bits of dried plaster no bigger than say a large potato, pop in your general waste bin.

danrv

FreeBear said:

danrv said:

Managed to get much smoother edges on this patch. Does depend on how even the surrounding wall is.

I find cleaning the tools after can be a long process as the plaster starts to dry on them. Also figuring out what to do with any leftover plaster but I do mix small quantities to avoid this.
I'm using three buckets - plaster mixing, water top up and cleaning water. 

Just don't tip it, or the dirty water, down the drain.

There's quite a lot of dirty plaster water to dispose of. I have a section of dug over soil in the garden for turfing so could tip it there.
Any large lumps of plaster I can let dry and then take to the recycling centre.

FreeBear

danrv said:

FreeBear said:

danrv said:

Managed to get much smoother edges on this patch. Does depend on how even the surrounding wall is.

I find cleaning the tools after can be a long process as the plaster starts to dry on them. Also figuring out what to do with any leftover plaster but I do mix small quantities to avoid this.
I'm using three buckets - plaster mixing, water top up and cleaning water. 

Just don't tip it, or the dirty water, down the drain.

There's quite a lot of dirty plaster water to dispose of. I have a section of dug over soil in the garden for turfing so could tip it there.

Got a section of garden that is slated for a layer of hardcore & gravel - That is currently where I'm disposing of my waste water. If plans change, I can always plant some alkali loving shrubs in that spot.

danrv

FreeBear said:

My first big wall. Chases and missing lumps from where skirting & picture rail removed filled with bonding coat. A base coat to level out the original "rustic" plaster, followed by two skim coats. Not looking forward to doing the arched alcove. Might end up using Fill & Finish for that...

Looks good.
I have a 1.9m x 2.3m landing wall that has a blown plaster line up the middle. 
That might be a case of plastering the whole wall. Will see how much of it comes off.
Judging how much to mix up I found a bit tricky. Was tending to do enough for a couple of hawks full so as not to waste any.

Quite pleased with the patch plastering. A mist coat will soon show any marks but it's a lot better than it was.

Eldi_Dos

Was just reading about the latest excavation in Pompeii, they have found a stack of building materials waiting to be used and pots of mortar filled ready for use.
No need to guess what type of mortar it was.

FreeBear

danrv said:

FreeBear said:

My first big wall. Chases and missing lumps from where skirting & picture rail removed filled with bonding coat. A base coat to level out the original "rustic" plaster, followed by two skim coats. Not looking forward to doing the arched alcove. Might end up using Fill & Finish for that...

I have a 1.9m x 2.3m landing wall that has a blown plaster line up the middle. 
That might be a case of plastering the whole wall. Will see how much of it comes off.
Judging how much to mix up I found a bit tricky. Was tending to do enough for a couple of hawks full so as not to waste any.

Measure up the area - 1.9mx2.3m is ~4.37m². For a ~2mm skim coat, you want to use two mixes using ~3l of water for each. Go for 3.5l for the first coat just to make sure you have enough, and 3l for the second coat.

A 25Kg bag of Multifinish covers 10m² @2mm and needs 11.5l of water. So roughly 1l per square metre. Always better to mix a bit more than you need rather than having to mix another batch half way through.

danrv

FreeBear said:

danrv said:

FreeBear said:

My first big wall. Chases and missing lumps from where skirting & picture rail removed filled with bonding coat. A base coat to level out the original "rustic" plaster, followed by two skim coats. Not looking forward to doing the arched alcove. Might end up using Fill & Finish for that...

I have a 1.9m x 2.3m landing wall that has a blown plaster line up the middle. 
That might be a case of plastering the whole wall. Will see how much of it comes off.
Judging how much to mix up I found a bit tricky. Was tending to do enough for a couple of hawks full so as not to waste any.

For a ~2mm skim coat

The Siraphite plaster as Stuart45 describes, seems to be quite varied in thickness. From 10mm up to 20mm in places. Just wondering if plaster needs to be that deep? Makes patching a bit difficult.

Most of it seems to be adhered to the wall quite well but in a few areas, it's popped quite badly. 
With the patch plastering, even two coats of 
sand/cement mix didn't get the level up as required. Ended up having to put the plaster on quite thick in places. Not really a skim as such.

With a prepared, complete wall down to the 
bare concrete block, I guess the plaster coat/s thickness needs to meet up with the ceiling, corner and door frame or whatever.
Maybe dot & dab plasterboard as suggested would be needed.

FreeBear

FreeBear said:

danrv said:

FreeBear said:

My first big wall. Chases and missing lumps from where skirting & picture rail removed filled with bonding coat. A base coat to level out the original "rustic" plaster, followed by two skim coats. Not looking forward to doing the arched alcove. Might end up using Fill & Finish for that...

I have a 1.9m x 2.3m landing wall that has a blown plaster line up the middle. 
That might be a case of plastering the whole wall. Will see how much of it comes off.
Judging how much to mix up I found a bit tricky. Was tending to do enough for a couple of hawks full so as not to waste any.

Measure up the area - 1.9mx2.3m is ~4.37m². For a ~2mm skim coat, you want to use two mixes using ~3l of water for each. Go for 3.5l for the first coat just to make sure you have enough, and 3l for the second coat.

A 25Kg bag of Multifinish covers 10m² @2mm and needs 11.5l of water. So roughly 1l per square metre. Always better to mix a bit more than you need rather than having to mix another batch half way through.

Just done the chimney breast. Calculated 3m², so bunged 3l of water in the bucket with the intention of doing the side (1m²). Was just enough for a single coat over the 3m² area.. Second coat, another 3l of water used.... Ended up putting a third coat (another 3l of water) on as the wall wasn't flat or level.

Got another 3m² section to do this afternoon, and then on to the sides & alcove - I'll probably leave those last two bits for tomorrow.