Room in Roof & Loft Insulation

As you can see the old loft insulation is terrible, smothered in dust and so are the stored items. How can this possibly be endorsed by the powers that be?

 We have all been educated that laying man-made vitreous fibres (MMVFs) on the loft floor is the normal thing to do. MMVFs are materials like rock-wool and fibreglass which over a fairly short period break down. 

Every time someone enters the loft space they will be ingesting a mixture of fibres, outdoor pollutants and possibly mould spores, definitely a place to avoid and often in more of a state than the shed in the back garden. 

Ask yourself, do I have loft insulation on the back of my loft hatch? In most cases, the answer is no. 

Logically heat rises, so the heat will funnel straight through the thin loft hatch and leave the roof making all that horrible loft insulation a complete waste of time. Not to mention all the voids left by the loft insulation being disturbed, for example, crushed under floorboards or moved by plumbers or electricians when doing work. 

So many people think they are well insulated however;  the truth is certainly very different. 

Separating the loft space from the home below is known as a cold roof solution but can create many other problems. Insects like wasps and hornets have ease of access, vermin love nesting under MMVFs and birds will find access to a home-owners loft if they can.

Another common issue is condensation in lofts being created by the loft insulation laid out on the floor. This can happen in three ways.

1. By having loft insulation entirely over the loft floor it can trap moisture-laden air within the property itself. This is more common in older properties, especially ones with solid walls. Tell tale signs are damp and black mould around the ceiling areas.
2. Interstitial condensation can occur within the loft insulation itself. The underneath of the loft insulation is warmed by the heating from below while the top remains cold in the loft space. Condensation can occur inside the loft insulation and the damp can travel through the joists, into the fabric of the home and also up the rafters.
3. The most common of the three is when heat travels through the loft insulation and the voids to meet the cold environment. The heat then condenses on the roof lining as in the picture. Roof timbers and roof lining can get very damp and mouldy and the timbers will eventually rot out if not noticed in time.

Because home-owners commonly avoid going into a cold-roof loft space they tend not to notice many of the afore mentioned issues until they are at an advanced stage. This can be, potentially very costly. 

If there is no roof lining or it's perished, as in the old tar paper shown in the picture, then a new roof lining will be required before any spray foam loft insulation can be applied. This is a pre-requisite of the British Board of Agrément and KIWA.

Once a new roof lining has been inserted it's ready for the spray foam loft insulation to be applied between the rafters. Moisture readings have to be 19% or below and before and after pictures must be taken to prove that a membrane is in place.

The insulation is an open-cell water-blown spray foam loft insulation that, after expanding at 100 to 1 comprises of over 90% air.

Once correctly installed it will create what is known as a warm roof solution. In warm roof construction the loft insulation is installed above the structural deck. This keeps the structural decking, usually constructed from timber at the same temperature levels as the internal temperature of the home. 

The environment of the loft space should have no noticeable difference to any other room in the home meaning huge energy bill savings and a great area to store items. Not only will you be retaining heat during the winter months you will also be keeping the property cool during the summer. 

Once the new healthy space has been created the old loft insulation becomes obsolete. The insulation can be removed and the floor area can be boarded to make full use of the new loft environment. 

If the loft is to remain a loft for storage purposes then it's perfectly ok to leave the new loft insulation exposed as in the picture.

If the loft is to be used as a habitable space then trimming the loft insulation and boarding over is recommended. This process is the same for room-in-roof or loft conversions.

It's worth noting that if you or a new owner want to convert the loft space at a later date then the loft insulation will already be in place, all it will need is the trimming and the boarding.