Preparation and drilling

Preparing and drilling prior to drilling internally, all obstructions should be removed, i.e., plastering and rendering. Plaster/render should be removed up to a line not less than 300mm above the last visible signs of dampness and/or salt contamination (using an electrical moisture meter) or 1 m above the d.p.c. whichever is the higher.

The positioning of the d.p.c. is vital if the damp proofing works ate to be effective. The d.p.c. should be placed at least 150mm above external ground level. If the external ground level is above the internal floor level it is necessary to lower the outside ground (permanently) or to incorporate in internal waterproof surface treatment, such as SSDP Water Proofing Slurry to cover the gap between the inserted d.p.c. line and the floor.

Holes should be drilled using 16-18 mm drill bits at overall spacings of 110mm and at an angle of depression of about 30°, finishing in a mortar bed at the level of the proposed d.p.c.. In solid walls up to 460mm thick drilling from one side to the thickness of the wall (and at the 30° angle), should result in a hole terminating 50mm or so from the far side. It may occasionally be advantageous to drill from both sides i.e.,random stonework with rubble infill or thick walls. Drilling should stop just over half way through the wall, the holes being at staggered centres of 110mm.

Prior to application SSDP Injection Mortar all drilled holes should be flushed out with water to remove any dust. SSDP Injection Mortar should always be injected into damp holes.

In walls less than 120mm thick, rather than drill holes, the mortar bed as the desired level is raked out to between one third and one half its depth. The mortar bed should be flushed with water to remove debris and the injection mortar applied by trowel into the joint. The mortar should be made up to a stiffer than usual consistency. The joint should be filled to within 8mm of the front face. Re-point using 3:1 washed sharp sand : cement using Salt Inhibitor Render Additive.

Application of SSDP Injection Mortar

A hand caulking gun is used. The nozzle of the gun is inserted into the holes to the full depth and slowly withdrawn whilst filling the hole with SSDP Injection Mortar. SSDP Injection Mortar should be stopped approximately 50mm from the top of the hole. Once all holes are to this stage it may be necessary to top up due to SSDP Injection Mortar finding its way into any voids or fine crack. Once SSDP Injection Mortar has set, the holes should be plugged up with 3:1 washed sharp sand : cement, using Salt Inhibitor Render Additive.

Mixing of SSDP Injection Mortar

Mix the SSDP Injection Mortar at the ration of 2 to 3 parts water by volume to 5 parts powder by volume. Add the water to the powder. Mix thoroughly until the consistency of smooth cream is achieved, using a mechanical whisk if possible. Allow to stand for a few minutes, the mortar will ‘false’ set. Re-stir, the mortar should remain useable for approximately 20 minutes with occasional further stirring. Do not add extra water to the mix when re-stirring. Do not mix more mortar than can be used within 20 minutes.

Re-plastering and decorating

Re-plastering using a salt retardant render additive if hydroscopic salts and residual moisture are to be successfully held back.

The substrate to be rendered should be prepared in accordance with the good practice. Surfaces should be clean sound and free from contaminating residues of gypsum plasters, bitumen coatings etc. apply two coats of render, the first being a 3:1 washed sharp sand : Portland cement mix Salt Inhibitor incorporated in the gauging liquid. Apply a minimum thickness of 10mm, second coat being a 4:1 washed sharp sand : Portland cement mix but without the Salt Inhibitor. A mortar plasticizer may be used if required. Apply to a thickness of 10mm. The finish coat should be porous skim plaster applied when the cement render coats are fully cured.

Once re-plastering is complete and dry, one coat of trade Matt emulsion can be applied (no oil based paints).

Storage and packaging

SSDP Injection Mortar is supplied in 25kg plastic tubs and should be stored in a dry enclosed area. Un- opened tubs have a shelf life of 12 months.

Health and safety

SSDP Injection Mortar contains ordinary Portland cement and is alkaline when mixed. In the case of contact with eyes or skin wash immediately with water. Obtain medical attention if irritation persists. If swallowed, do not induce vomiting, wash mouth out and drink water. Seek medical attention. Rubber gauntlet type gloves should be worn and goggles and mask should be worn during mixing. Keep away from animals, children and food stuffs. For further information see separate Health Safety Data Sheet.