On 18 Jun, 13:57, Maris wrote:
On Thu, 14 Jun 2007 09:59:42 -0700, Chris George
wrote:

I have used in my house DryZone from Safeguard Chemicals. It workeed.
It only requires a bit of commonsense to follow the instructions and a
dirty great big applicator gun with lance on the end. You could rig up
your own system with aluminium or steel tube and a LARGE mastic gun.
Test the plaster as follows with a damp meter (hire or borrow) every
few cycles of humidity high and low and see if it alters the readings.
Test the pattern of existing readings - If there is a "high tide" mark
somewhere 300 to 1000 above the ground with lower readings above and
below - that is probably rising damp!

The only problem with this method is that the fluid will just shoot
away into an abyss if there are any irregularities in the old mortar
(and there usually are), which I discoverd to my cost (and DPC fluid
isn't cheap). If I need to repeat the treatment (and the indications
are that I will) I will use those wax stick things that slowly melt
and permeate the bricks/mortar course much more effectively.

DryZone operates on precisely the same principle! It is a gel-like
cream which disperses slowly over the next few days. It does not
operate like a fluid but clearly to be injected has fluid (albiet very
sluggish) properties. Its spread far exceed frozen sticks - (if that
is what you are referring to by "wax" sticks. If it is indeed wax the
melting point is such that at NRT it wont melt so I assume you are
referring to AQUEOUS sticks with "wax-like" ingredients. If I am
wrong, I would be interested in the trade name.



If you replaster use a 3:1 render with Sika No 1 water proofer and you
wont go far wrong
In fact you could do that without the dpc and probably get away with
it but not recommended.
Good luck
Chris

I wouldn't recommend using render - you could end up with condensation
problems instead.

Condensation occurs due to the dew point having been reached and I
have never found in the last 30 years of specifying both an example
where the difference in U value between Limelite Reovating (a
vermiculite-containg sand cement render) and a cement render has
tipped the balance to condensation forming. Limelite Renovating is a
great product (be careful not to be confused with other manufacturers
"renovating" plasters based on gypsum!)but there are plenty of
occasions where it is not suitable and this is one. It has practically
no capacity to prevent salt migration to the surface and efflorescene
is common. Its adhesion is questionable where you have variable
absorbent substrates - just try tapping it after and you will find
more "hollow" sounds than with render. Where there is limited risk of
salt contamination and no lateral penetration - go for it if you can
find it but don't fear appropriately specifed sand cement render. If
you really want a good product where limelite would be OK why not be a
purist and put on an original lime render using a lime putty (NOT
bagged lime!) but that is quite another post into which I have not
intention of further travel!


In my previous house I used Limelite Renovating
plaster, which worked a treat. I don't think they make it any more but
I think there are equivalents. I am busy tearing off the render off my
damp party wal and it is not going back on. The previous owners had
made doubly sure that the damp would remain in the wall by using vinyl
paint on top of the render!

Maris