The composition of black ash mortar — commonly used up until the 1920s — has varying amounts of sand in its composition.

As the active chemicals in Dryrod Damp-Proofing Rods require sand to be effective, the effectiveness of a Dryrod DPC in black ash mortar is variable. If you’re planning to install a remedial DPC in black ash mortar, please get in touch for personalised advice.

For internal installation: The "BS6576: Code of practice for diagnosis of rising damp in walls of buildings and installation of chemical damp-proof courses" recommends that treated walls should be left for as long as possible following DPC treatment in order to allow the wall to dry out as much as possible before replastering.

However, some replastering solutions are not an issue: Drybase Flex, Express System, Oldroyd Xp and Drybase Plaster Membrane are either barriers or not in direct contact with the Dryrod Damp-Proofing Rods.

For plaster based solutions like Dryzone Damp Resistant, Fast Set and Hi-Lime Plasters, it is recommended to wait 4-6 weeks to allow the liquid active to fully disperse and avoid any staining of the plaster.

Alternative solutions include:
A dab of Drybase Liquid DPM onto the ends of the rods to prevent the active chemicals spreading onto recently applied plaster.
Plugging the insertion hole with waterproofed mortar.
Plugging the insertion hole with Stormdry XR Mortar Mastic injected into the hole before repointing with mortar.

For external Installation (if the injection has been made externally): Effectively the same as above If using Dryzone DPC cream then DPC plugs can be fitted to the external drill holes.

Dryrod Damp-Proofing Rods can be inserted into stone, concrete or thermal / breeze blocks rather than the mortar course. You may choose to do this if the mortar course is too narrow to drill a 12mm hole into, or if the wall is concrete. The drilling centres will need to be reduced to 100mm instead of the usual 120mm spacing to account for the increased density in the substrate.

Yes, they can be. However, keep in mind that the chemical DPC should be created externally in the first mortar course at least 150mm above the external ground level.

Internally, the chemical DPC should be created in the lowest accessible mortar course above a solid floor, or in the lowest accessible mortar course below the timbers supporting a suspended timber floor. These are both typically lower than standard DPC height.

If the chemical DPC is created from the outside of the wall through to the inside of the wall, or vice versa, it is highly likely that the chemical DPC will be created at an incorrect height which may in turn compromise its performance.

The solution to this challenge may involve the creation of two separate DPCs at appropriate heights in a solid wall. Please contact our technical team for more information about your particular situation.

No, this is an invisible process. Assuming that the Dryrods have been installed correctly in accordance with our installation guidelines, there should be no signs that the remedial DPC has been formed.

Dryrods should be installed at a minimum temperature of 0°C and up.

It is important not to install them if the temperature is due to drop below 0°C in the next 57 days.

We do not recommend Dryrod Damp-Proofing Rods installation in wet frozen walls in cold temperatures as this can affect the dissipation of its active ingredient. It is preferential to wait until the temperatures have risen, the walls have warmed up, and any ice that may have formed in the wall has melted before using Dryrod Damp-Proofing Rods to create a chemical DPC.

Once the packet has been opened, any unused Dryrod Damp-Proofing Rods should be kept in the packet, and the packet itself should be kept in an airtight container or bag. Dryrod Damp-Proofing Rods should be used within 3 months once opened.