Does Chemical Damp Proofing work?
Property Repair Systems - 01626 331351 - where you can speak to real people
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Does Chemical Damp Proofing work? Property Repair Systems - 01626 331351 - where you can speak to real people
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| Chemical Damp Proofing with silicones WHY OUR NEW GENERATION INJECTION CREAMS ARE BETTER THAN LIQUIDS The technical review below summarises the problems of the last generation of liquid damp proofing systems. Our New Generation Creams are infinitely better for the following reasons:
For help with Silicone Creams call our experts on 01626 331351. DOES CHEMICAL DAMP PROOFING WORK - PRESSURE INJECTION USING LIQUIDS Unlike a physical damp-proof course these injected liquid damp-proof courses do not form a 'discrete impermeable plane', but more of a 'diffuse band'. When fluids are injected into a heterogeneous substrate such as brick/mortar they do not totally fill up the porous structures and neither do they completely push out the water in front of the advancing injection fluid as is so often claimed. Instead, the fluid tends to 'finger' within the substrate, a process known as 'viscous fingering'. The fingers of the injected material form when the fluid takes the lines of least resistance such as the larger pores and cracks. Unfortunately, such pathways are not the most important elements in the conductance of water up the wall. Furthermore, the damper the substrate the greater this fingering is likely to be, especially with solvent based systems since these are not miscible with the resident moisture. Fingering is also increased by injection at high pressure. Reduction of the phenomenon is obtained by low pressure injection or, better still, by gravity diffusion of the dpc fluid. For help with pressure injected damp proof courses call our experts on 01626 331351. WHY PRESSURE INJECTION CAN BE INCOMPLETE The result of the damp-proofing fluids forming fingers give rise to non-impregnated 'pools' within the wall through which water can continue to rise. In the case of pressure injection damp-proof courses, this suggests that it is unlikely that the diffuse band of the damp-proofing agent will be totally complete. The resultant chemical damp-proof course may therefore not stop rising dampness by causing an immediate cut-off of rising water above the damp-proof course like that effected by a physical damp-proof course. Instead, a relatively rapid decline in the moisture gradient should occur above the inserted chemical damp-proof course due to the 'control' exerted. Thus, in practice, the rising ground water should be reduced to such a level that, in association with specialist replastering, it should no longer cause decorative spoiling or damage. For help with pressure injected damp proof courses call our experts on 01626 331351. WHAT ELSE AFFECTS LIQUID SYSTEMS? The efficacy of the water repellent damp-proofing systems can be affected where there are detergents (surfactants) impregnated into the wall by, for example, past leakage from sink waste pipes. A similar problem may occur when walls are sterilised against dry rot infection by biocide formulations containing surfactants. The overall effectiveness of a remedial damp-proof course can be investigated by examining the relationship between the distribution of free moisture (water due to rising dampness or other source of active water ingress) and contaminant salts (chloride and nitrate). Where rising dampness is still active capillary moisture will be found to the full height of salts. The absence of capillary moisture in the presence of salts arising from rising dampness indicates that drying back has occurred and that the damp-proof course is effective. Intermediary stages are also found which demonstrate different degrees of control of the rising dampness. If chloride and nitrate are not detected in a sampled profile it is possible that the ingress of moisture is due to recently developed rising dampness or more likely through rainwater penetration, condensation, plumbing defect or other sources. For help with pressure 'salts' analysis call our experts on 01626 331351. TESTING A CHEMICAL DAMP COURSE When evaluating the efficacy of remedial damp-proof courses care must be taken not to misinterpret electrical moisture meter readings; high readings might not indicate that the damp-proof course itself has failed. They may reflect a number of possibilities including contaminated or inadequate plasterwork. Thus, an accurate assessment of the efficacy of a damp-proof course can only be undertaken by determining full moisture profiles linked with analysis for contaminant salts. It is also important to give consideration to the expected performance and limitations of the installed system as described above. NOTE: It is identified in BS 6576:1985 that where timber suspended floors are encountered the damp-proof course must be injected, where possible, below joist level; this is to protect the embedded timbers from dampness and the risk of fungal decay. However, given the likely efficacy of injection systems the embedded joist ends could still remain in contact with damp masonry even if above the injected damp-proof course and may therefore remain at risk to fungal decay. It would be considered prudent that in all cases where a damp-proof course is installed in relation to a timber suspended floor, action is taken to protect any embedded timbers just above and certainly below the injected damp-proof course to prevent potential decay! Boron Gel, injected Boron Paste and the insertion of a plastic membrane can all be used to protect vulnerable joist ends and bearings. Do NOT bag joist ends in plastic - this can lead to serious decay, due to condensation and lack of breathing. For help with testing a damp proof courses call our experts on 01626 331351. Learn from the UK's greatest Expert: become your own expert - save money. Quick DIY Master Class in Dampness and Condensation - become your own Expert in 1 hour! Buy our "Dampness in Buildings" reprinted book by the great expert Graham Coleman. A great read, short and to the point. Click here to buy the reprint. Home | Damp| Plastering | Membrane | Damp Meters | Anti-Mould Additives |Privacy Policy | Returns Policy | Contact Property Repair Systems Unit 3, Olympus Business Park, Kingsteignton Road Newton Abbot, Devon, TQ12 2SN T: 01626 331351 F: 01626 331143 E: help@propertyrepairsystems.co.uk Other Property Repair Systems Group Web Sites: www.boron.org.uk - how to use Boron based products to control rots and insect attacks in wood www.deck-treatment.co.uk - how to treat patio decks and yacht decks www.drywallandfloor.co.uk - how to fit plastic dimpled sheets to damp walls to provide a new, dry decorative surface. www.dryrot.biz - how to cure and prevent Dry Rot www.epoxy-info.co.uk - epoxies, polyesters and polyurethanes for all applications www.joist-repair.co.uk - how to quickly repair joists and beams of any size www.furniture-outdoors.com - all weather cane garden furniture, luxury Danish designs www.joist-repair.co.uk - how to quickly repair joists and beams of any size www.propertyrepairsystems.co.uk - fire retardent paints, hygiene products, metal bracket manufacture, crack injection www.timber.org.uk - systems of repair, with step by step methods www.timber-repair.co.uk - how to repair timbers in buildings without wrecking the place www.woodworm-info.co.uk - how to kill and prevent woodworm and death watch beetle |
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