Internal Wall Insulation

Lawtech supplies and installs internal wall insulation.  There are two main ways to insulate a solid wall internally; either with rigid insulation boards or with a stud wall.

We will first assess the condition of existing indoor walls.  Problems with penetrating or rising damp must be resolved in advance, as these both arise from defects within the building structure.  All repairs must be carried out prior to installing the insulation.  Insulation must never, in any circumstances, be used to cover, hide or isolate damp as it is highly likely to lead to more serious problems in the future.  Lawtech will indentify problems and advise on the best course of action.

Condensation is an important consideration.  When warm air from inside a home meets a cold surface, condensation will form.  Fitting internal wall insulation stops the heat from reaching the wall, so the wall will be a lot cooler.  Where insulation is to be applied on the inside of an internal wall, Lawtech will apply a vapour barrier to prevent moisture from the air inside the property from forming on the cold exterior wall.  

Consideration must also be given to supporting heavy fixtures like kitchen units, radiators or wash basins.  Where there is no need to support such items, rigid insulation boards may be fitted.  If, however, heavy fixtures are to be supported, a stud wall may be used.  Applying insulation directly to the wall involves fitting plasterboard, backed with rigid insulation, onto the inside of walls.  Typically the insulation will be made of either expanded or extruded polystyrene (EPS or XPS), polyurethane or phenolic foam.  The insulation will be at least 60mm thick to meet recommended standards and may be up to 100mm thick.  Prior to installation, it is crucial to prepare the wall that is to be insulated.  The surface must be flat.  If the existing plaster has been removed, exposing uneven brickwork, the wall must be plastered or rendered.  Once the wall is flat, the insulation boards can be fixed straight to it using continuous ribbons of plaster or adhesive. Additional fixings are used to hold the boards firm, and the joints between each board are sealed to prevent air leaking through to the solid wall. With stud walls, a metal or wooden studwork frame is attached to the wall and filled in with mineral wool fibre and covered with plasterboard. It can then be plastered over, ready for redecoration.

Mineral wool insulation, which is also used to insulate lofts, is a less powerful insulator than rigid insulation boards. So, to provide the recommended level of insulation, the mineral wool ‘filling’ needs to be at least 120mm deep. This makes stud wall insulation thicker than rigid insulation boards, which means it will affect the size of your room a little more. But on the plus side, a stud wall is strong enough to hold heavy fittings. Rigid insulation boards, by contrast, would need lengthy mechanical fixings that reach all the way from whatever you might want to support to the outer solid wall.

For further information on internal wall insulation please contact us.

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