Rising damp

TRI-GEL is a unique chemical Damp-proofing product for injection into brickwork etc. for the control of rising dampness. Tri-Gel is based on an established and time proven active ingredient and is formulated in a special way to produce a thixotropic gel. The gel is injected into 12mm holes drilled into the mortar course at the required DPC level.

A. TRI-GEL Chemical D.P.C. Injection

The Tri-Gel d.p.c. injection system is fast, clean and effective. Tri-Gel is a low odour, water based damp-proofing treatment for walls affected by rising dampness. Tri-Gel is injected into the mortar bed between bricks, stones or blocks via horizontally drilled holes to form a continuous barrier to the passage of water from the ground. Being water based and water soluble, Tri-Gel is able to diffuse naturally into damp substrates. After injection, Tri-Gel reacts to form a water-repellent Silicone resin network within the capillaries of the substrate. This network is permeable to water vapour which means that the walls can ‘breathe’ and thus dry out naturally.

Treatment of Rising Damp
Installation should, wherever possible, follow the guidelines laid down in BS6576:1985 ‘British Standard Code of Practice for Installation of Chemical Damp-Proof Courses’ and the BWPDA code of practice; The Installation of Remedial Damp-Proof Courses in Masonry Walls.

Injection is achieved into pre-drilled holes. The holes are drilled horizontally into the mortar course at the determined height for the d.p.c. The holes are of 12mm diameter at 100 to 120mm centres and to a depth of within 20-40mm of the opposite face. Ideally drilling should coincide with the base of all perpends of the course selected. In virtually all cases solid brick walls can be drilled and treated from one side only in a single operation. Cavity walls would normally be treated from both sides. Complementary vertical d.p.c.'s, to the required height, will be positioned as necessary to isolate the treated walls from adjoining untreated areas, e.g. semi-detached and terraced properties, abutting garden walls and fireplaces/chimneys where access to the back or sides of the structure is not possible.

As with all remedial damp proof course systems the adequate removal and replacement of salt contaminated plaster is an essential requirement. Plaster should be replaced in strict accordance to our relevant re-plastering specification.
It should be borne in mind that whilst the insertion of a chemical d.p.c. will inhibit further moisture from rising up the wall, the moisture present will take time to dry out, a guideline is one month per 25mm of wall thickness. Any decoration following treatment should not be carried out until the new plaster has fully dried out and should then be regarded as temporary; we recommend a single coat of non-vinyl, water-based, matt emulsion. Final decoration should not be carried out for at least 12 months following treatment.

B. Injection Mortar System

Special Properties
For rubble filled or random stone wall construction.
Suitable for saturated walls.
For use in walls unsuitable for pressure injection systems.

Treatment of Rising Damp
Injection mortar is a specially formulated compound which, when mixed in the correct proportions with water and inserted as described, will create a chemical damp proof course in walls above ground level. The process described in general terms can be effective in stopping rising damp in buildings that lack an orthodox dpc or the existing dpc has broken down in brickwork or stone and the wall is not heavily impregnated with hygroscopic salts. This system is particularly useful in random stone wall constructions where a central core of rubble exists or in any other situation where conditions preclude the sole use of other injected dpc systems.

Any high ground levels at or above internal floor levels should be reduced to a minimum of 150mm below internal floor levels. In most cases any external rendering will be removed to expose the dpc line.

The internal dpc line will be exposed by the removal of skirtings and any other obstacles to effective treatment.

Plaster affected by rising dampness should be removed to a height of 1 metre or 380mm above the maximum level of rising dampness. This is to avoid the possibility in time of hygroscopic salts impairing the efficiency of the treatment. Plaster should be replaced in strict accordance to our relevant re-plastering specification.

Installation is achieved by way of drilling 19mm holes, at the intended dpc level, at an angle of depression of between 20º and 30º to a depth equivalent to the thickness of the wall. To avoid damage, where possible drilling is started in the mortar line. Normally drillings will be made into each side of the wall at a maximum spacing of 230mm, the opposing drillings being staggered to give an overall spacing of 115mm. Where access is restricted drillings are made from one side of the wall at maximum centres of 115mm. The drill holes are flushed out with water to remove dust and ensure thorough wetting prior to the insertion of the injection mortar. Half brick walls will not be drilled but the mortar bed-joint will be raked out to half its depth and filled with injection mortar. Complementary vertical dpc's, to the required height, will be positioned as necessary to isolate the treated walls from adjoining untreated areas, e.g. semi-detached and terraced properties, abutting garden walls and fireplaces/chimneys where access to the back or sides of the structure is not possible.

It should be borne in mind that whilst the insertion of a chemical dpc will inhibit further moisture from rising up the wall, the moisture present will take time to dry out, a guideline is one month per 25mm of wall thickness. Any decoration following treatment should not be carried out until the new plaster has fully dried out and should then be regarded as temporary; we recommend a single coat of non-vinyl, water-based, matt emulsion. Final decoration should not be carried out for at least 12 months following treatment.