Insulationzzz

As the weather starts to turn and it becomes pretty cold during the day (rather than just at night) it’s time to talk about insulation.

For me this is probably the least interesting of all the subjects I’ll be covering in my quest for the energy efficient sustainable house. But it is also one of the most important as insulation can be the most cost effective way of making the biggest difference to your energy consumption (and therefore your bills).

As far as I can tell there is a type of insulation for all the different surfaces of your house. So roof / loft insulation, wall insulation, and floor insulation. Each type of insulation has different products available depending on your house and your requirements.

Roof Insulation
This comes in different types, but the most common and easiest to install (you can do it yourself) is blanket loft insulation that comes in big rolls. The important thing is to make sure it’s 270mm thick. It can be placed in between joists and then another layer can be placed on top.

Otherwise if you’ve got a funny shape loft with hard to access areas you can get loose fill loft insulation (again you can do it yourself). This is loose material that you spread out. It’s recommended to use 200 litres per square metre to a depth of 200mm (20cm).

Or you can get blown fibre loft insulation, which is similar, but needs to be professionally installed.

Finally there is sheet loft insulation, which is for the sloping sides of roofs and can be placed between the roof rafters and then covered in plasterboard. I think this is especially good if you are converting the loft into an extra room and are concerned about the loft losing heat and not just keeping it trapped in the rest of the house.

Wall Insulation
The kind of wall insulation you get depends on the kind of walls you have. Newer houses tend to have cavity walls, so the wall is made of two layers of bricks with a gap or ‘cavity’ in between. In this case you can get cavity wall insulation which is cheap and effective. They drill a hole into the cavity and blow the insulation in then fill up the hole afterwards.

If you have an older house then they might have solid walls (they were built like this up until the 1930s). In which case you are unlucky, as there are two types of insulation available to you but they are both far more expensive and labour intensive to install. You can get internal or external wall insulation. The external insulation is insulating cladding that can change the look of your house on the outside, but can be more effective than internal insulation which can leave gaps where internal walls meet the outer walls. The internal insulation is insulated dry lining which would need to be applied internally to the outer walls.

Basically if you have solid walls you should hope you have a terraced house as it cuts the number of walls to worry about by half (as long as you don’t mind sharing heat with your neighbours).

Other wall types like timber frames can effectively be treated as solid walls.

Floor Insulation
Floors either tend to be concrete or raised timber flooring. For concrete you can lay a damp-proof membrane, then rigid insulation on top, then cover with chipboard plus your desired floor covering. For raised timber flooring you can lay mineral insulation in between the joists in much the same way as you would with blanket loft insulation (mentioned above).

Finally for both types of flooring you can buy some sealant to fill in any gaps between the floor and the skirting board where heat may be escaping.

If your house is over two floors you don’t need to insulate the floor of the upper level, as long as the space below is heated (i.e. a living room). If the space below is not heated (like a garage) then it is worth putting in insulation in the floor of the room above.

That about covers it for insulation! Or at least it’s as much as I can stomach researching it until we have a house and know what kind we’ll need.

And on that note, we have had an offer accepted on a house! Things are still in the earliest stages, but watch this space. Relevant to this post, I think the house has solid walls, so insulating them will be expensive… Also floor insulation has been recommended, as you can see on the EPC snippet below.

My next blog post is likely to be on boilers. Like insulation this was not a subject I was particularly interested in until recently when ours stopped working and I had to have freezing cold showers for a couple of days…

NB: the girlfriend is not fully satisfied with this post as it doesn’t cover the environmental impact of the different insulating materials, or air flow and insulation / double glazing with regards to damp proofing. But never fear, I will broach these topics when I revisit insulation once we have our futurefitting house (oh joy).