Damp Proofing Course - affordable Damp Prevention in Burnley Nelson Colne and Padiham by Totally Plastered

The UK is one of the wettest countries and damp caused by rain water is a big contributor to property maintenance issues for plasterers. Burnley, Nelson, Padiham and Colne are situated in and around water sources such as rivers, canals and reservoirs so it is not surprising that there are many reports of damp and rising damp in properties.

Damp proofing Burnley

What is Rising Damp?

Rising damp in property can occur because of  the failure of an existing damp proof course, bridging due to the raising of external ground or internal floor levels, or in older buildings, the complete lack or absence of any damp proof course.

Brick, stone and mortar are porous building materials  which will allow damp from the ground to rise by capillary action, carrying with it ground salts including chlorides and nitrates. These salts from the ground can absorb moisture from the atmosphere leading to wall dampness in conditions of high relative humidity. This damp can ruin decor and break down internal plastering. In older days, stone-slab was mostly used as DPC material.

Modern damp proofing courses are generally of three types:

1) Chemical damp proof treatment – Recommended for most types of walling, a chemical is injected into holes drilled at intervals in the wall.
2) Injection mortar/creams – Ideal where a good sized bed joint is visible.
3) Electro osmotic treatment – An active system that introduces a very small electric current into the wall that pushes moisture downwards.

Building standards in the UK require most new buildings to incorporate a DPC/DPM at the time of they are built. This may consist of a thin strip of plastic, a course of engineering brick or slate, or a layer of bitumen.

Materials widely used for damp proofing include:Damp Proofing Colne, Nelson Burnley Padiham

Flexible materials like butyl rubber, hot bitumen, plastic sheets, bituminous felts, sheets of lead, copper, etc.
Semi-rigid materials like mastic asphalt
Rigid materials like impervious bricks, stones, slates, cement mortar or cement concrete painted with bitumen or PVA, etc.
Mortar with waterproofing  or water resistent compounds
Coarse sand layers under floors
Continuous plastic sheets or membranes under floors

A DPC is usually a thick plastic strip bedded into the mortar between two courses of bricks or blocks. It can often be seen as a thin plastic line in the mortar near ground level.

A DPM is usually a thick polythene sheet laid under the floor slab, to allow the slab to dry out and keep out groundwater. It is often laid on a bed of sand, to prevent the sharp edges of the hardcore damaging it.

To create a continuous barrier, pieces of DPC or DPM are welded together. In addition, the DPC is welded to the DPM around the outside edges of the ground floor, completely sealing the inside of the building from the damp ground under it.

Damp Proof Course NelsonIn a cavity wall, there is usually a DPC in both the outer layer and inner wall. In the outer wall it is normally 150-200mm above ground level (the height of 2-3 brick courses). This allows rain to form puddles and splash up off the ground, without saturating the wall above DPC level. The wall below the DPC may become saturated in rainy weather. The DPC in the inner wall is usually below floor level, (under a suspended timber floor structure), or, with a solid concrete floor, it is usually found immediately above the floor slab so that it can be linked to the DPM under the floor slab. This enables installation of skirting boards above floor level without fear of puncturing it. Alternatively, instead of fitting separate inner and outer DPCs, it is common in commercial housebuilding to use a one-piece length of rigid plastic, (albeit an angled section), which fits neatly across the cavity and slots into both walls (a cavity tray). This method requires the need for weep vents to enable rainwater ingress to drain from the cavities otherwise rising dampness could occur from above the DPC.

Many of the damp proof courses in Colne were replacing Damp proofing In old buildings where there may be a DPC made from lead. The DPM may be non-existent, leading to damp problems, mold health issues or generally a poor indoor air quality, or it may rely on an impermeable floor finish such as ceramic tiles to keep most of the damp out.[4]

Where a DPC is absent or inadequate, there are various means of retrofitting one. A common method in masonry walls is to drill holes into the wall at regular intervals and inject a penetrating liquid (e.g. silicone) into the holes. The chemical is absorbed into the masonry, where it cures to form a waterproof barrier. More recently, damp-proofing creams have been introduced which are faster to install and do not require specialized pumping equipment. Whether in liquid or cream form, the effectiveness of chemical damp-proofing products depends on a number of factors including product strength, the types of active ingredients in the formulation, the delivery system (e.g. solvents and surfactants), and the suitability of the system for the substrate that it is being injected into. Some forms of the chemical are odour-free; others have a strong odour.

Damp proofing remedies include:

Silane diffusion: Utilising a concentrated thixotropic silane / silicone ‘cream’
Siliconate transfusion: A gravity fed system with no wastage via hidden voids
Siliconate injection: Recommended occasionally for single brick walls

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