lime plastering???

[naughtynick]

About 8 years ago we restored and extended an old school. The new build was plastered using modern techniques dot and dab etc. The original walls were stripped back to bare brick (old Suffolk reds about 14" thick). My plasterer had never used lime but said he would spread as long as I mixed. I used dry hydraulic lime with plastering sand I also mixed in some of the old removed plaster from the walls. We put on an initial coat at about 3/8 to 1/2 " thick and finished with one top coat at about 1/16 to 1/8". Didn't put any hair or other fiber in the mix. It seems to be standing the test of time any comments welcome!
One of the chimney breasts has started to blow around skirting board level, looks like damp. I am wondering about supporting the chimney breast and removing a layer of bricks at dpc level and fitting some dpc material. Is this approach ok in view of the fact that the rest of the old part of the house has either no sign of a dpc or in some areas there is a poured bitchumen dpc.
What sort of beads are recommended for lime plaster work, originally we had wood beads but know they are a mix of either metal or plastic.

Nick

 

[martinemj]

how did you finish the original lime render ....trowel..float or sponge ?

beads/corners ....depending on period of house either wood ,stainless steel or rounded .


welcome to the forum by the way

 

[malc]

the school building sounds of no interest, and if it is not listed.
i would not remove the bricks to put in a dpc. i would remove the skirting board and inject a damp proofe cream.

welcom to the forum

 

[naughtynick]

In the first room the plaster was finished with a sponge because my plasterer has used this technique on exterior rendering previously. On later rooms I asked him to trowel finish which he did with a metal trowel, this worked out much smoother and less time consuming (cheaper for me!).
I have looked at the problem area and the red suffolk bricks are basically perished they won't take a drill without breaking up/crumbling, think I will replace them and insert a dpc at the same time?

 

[carlos]

Chimneys are often problematic with damp. Is it capped off and vented? Or still in use with a open fire?


Just a quick note, when you inject a DPC cream you inject it into the mortar joint. This should not damage the bricks in anyway.

 

[naughtynick]

The chimney is still open/vented and is protected at the top from the majority of rainfall, it isn't used anymore. The damp is coming up from the ground rather than through the chimney breast onto the walls.
carlos thanks for the info re the dpc cream, in light of that i'll take another look at the problem.
Thanks for all the feedback and the welcomes

 

[carlos]

Not being picky mate but you really need to sort the top out first. A proper cowl will stop ALL the rain getting down the chimney and vent it at the same time.

https://www.google.co.uk/search?q=c...-Q7AaAloCABQ&ved=0CAoQ_AUoAQ&biw=1366&bih=643

An air brick should also be install at the bottom of the chimney to allow a through air flow.

While your up there check the flashing too.

How do you know the damps rising?