Insulation is the only improvement to a home that works twenty-four hours a day, consumes nothing and never has to be switched on. It is also the most invisible: when it is done well, nobody sees it; when it is missing, you feel it in every bill and in the room there is no way of cooling down in August.
At Grupo Construcciones Alicante we install thermal and acoustic insulation in homes, commercial units and buildings across Alicante and the province. We work from the outside, from the inside or by filling the cavity, depending on what each case allows, and we choose the material for how it actually performs at that point, not for how quickly it goes up.
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The effect most appreciated here is in summer. An insulated home takes far longer to heat up and holds the cool overnight, so the air conditioning runs less and reaches temperature sooner when it does. In top-floor flats the difference is so marked that it changes which rooms actually get used.
Acoustic insulation is the other half, and often the one that adds most to quality of life. Many neighbour disputes are not solved by talking to the neighbour: they are solved with a properly built lining on the party wall, or with a floor treatment if the problem is footsteps. And there is a further benefit people forget: good insulation removes the cold surfaces where condensation forms, and with them the mould.
Insulating well starts with knowing where the energy is being lost. This is the process:
We identify where the heat or the noise gets in: façade, roof, windows, blind boxes or party wall. Insulating the wrong element is spending money without feeling the improvement.
A fixed quote stating the system, the material and the thickness, which is the figure that actually determines the result and the one most quotes leave out.
We prepare the substrate and deal with any active damp first: insulating over a wet wall traps the problem inside and makes it worse.
We install the insulation making sure it is continuous, with no open joints or missed areas, and treat the junctions specifically, which is where the savings are otherwise lost.
We check continuity before closing up and, on acoustic work, confirm there are no flanking paths through socket boxes or unsealed junctions.
We close up and finish the surface, and provide the data sheets for the materials installed with their thicknesses and performance, which you will need for an energy certificate or a grant application.
External insulation (EWI). The most effective system: it wraps the building from outside, eliminates the thermal bridges at floor edges and columns and takes up no internal floor area. It also protects the façade. Its drawback is that it changes the external appearance and, in a block of flats, requires the owners’ agreement and scaffolding.
Internal insulation. Where external work isn’t feasible, the wall is lined internally with mineral wool and board. It is quick, can be done room by room and needs nobody’s permission, although you lose a few centimetres and it doesn’t fully resolve the thermal bridges at the junctions.
Cavity injection. If the wall has a cavity, it is filled from outside or inside with mineral wool or cellulose through small holes that are then made good. It is the least invasive option and the cheapest, done in a day and without emptying the house. It is worth checking with a borescope first that the cavity exists and is clear.
Roofs. This is where most heat gets in during summer on a top floor. It can be insulated above (inverted roof, with the insulation protecting the waterproofing) or below, within the suspended ceiling, which is cheaper but leaves the slab storing heat.
Every material has its place. Mineral wool is the reference where thermal and acoustic performance are both needed, because its fibrous structure absorbs sound; it is what we use in linings and partitions. EPS and XPS insulate very well against heat but not against noise: XPS is also unaffected by moisture, making it the right choice under slabs and in inverted roofs. Sprayed polyurethane gives the best performance per centimetre and adapts to irregular surfaces, which is very useful on pitched roofs and exposed party walls.
On thickness: it is what determines the result, and yet it is the first thing cut to trim a quote. Going from four to eight centimetres costs very little in the context of the whole job and completely changes the behaviour. If you are going to do it once in your life, do it with enough thickness.
And an important warning: insulating is not the same as ventilating. A very well insulated home with no ventilation accumulates internal moisture and condensation appears at the coldest points. So when insulation and new windows go in together, ventilation should be planned, even if only with trickle vents in the windows or a timed extractor in the bathrooms.
Insulation work we carry out regularly in Alicante and the province:
If the wall has a cavity, yes: injection is done through small holes that are then made good, completed in a day, with no rubble, without emptying the property and at a very contained cost. The first step is confirming with a borescope that the cavity exists, how wide it is and that it is clear. If the wall is solid or the cavity is full of debris, the options are internal lining or external insulation.
It depends on the system and the element being insulated, but as a rule: on a façade, the more the better, and below four centimetres the effect is modest. On a roof it is worth being more generous, because that is where most heat enters in summer. We give you the recommended thickness with its cost implication, so you decide seeing the real difference between one option and another rather than blind.
It depends on the type of noise. Airborne noise (voices, television, music) is greatly reduced by a properly built lining with mineral wool and board, separated from the wall with no rigid contact. Impact noise (footsteps, chairs dragging, knocks) travels through the structure and cannot be solved from below: it has to be treated in the floor of the property above with an acoustic underlay. It is important to know that before spending money expecting a result the system cannot deliver.
An internal lining takes between six and ten centimetres depending on the system and the insulation. In a medium-sized room that means losing a little over a hand’s width on the treated walls, which are normally only those facing outside or the problem party wall. If that loss is critical, cavity injection or external insulation are the alternatives that take no space at all.
Against condensation, yes: removing the cold surfaces where water vapour condenses gets rid of the mould patches typical of corners and behind furniture. Against damp from leaks or rising damp, no: there you have to stop the water getting in first. Insulating over a wall that leaks traps the water inside and makes it worse, so we always establish the source before covering anything up.
Cavity injection in a home takes a day. Internally lining the external walls of a flat takes three to five days, plus decorating. Insulating a flat roof depends on the area but is usually resolved in one or two weeks, and external wall insulation runs with the programme of the façade refurbishment and its scaffolding.