On Tue, 19 Jun 2007 00:04:22 -0700, Chris George
wrote:

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.

We are probably talking about the same thing. I couldn't remember what
the contents of the sticks was but sticks they were.



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!

Condensation does not depend so much on the U value of the
construction as on the conductivity of the surface. i.e certain
surfaces (e. granite, metals) will always feel cold to the touch (and
therefore likely to induce condensation) whilst others such as timber
will feel warm. The U value does, of course, play its part.
Limelite renovating plaster was developed for damp situations
(something also referred to in a forum about Limelite that I just
viewed) whilst standard Limelite backing plaster was for non-damp
locations. I will concede that it is sometimes a bit prone to losing
its adhesion. My main reason for using it (and Limelite backing) was
it insulation properties. Carlite has similar properties, of course,
but is as hygroscopic as they come.

Maris