Thursday, 27 April 2017

FAQ's "How can I better insulate my house?"

How to get lower heating bills and a greener house

This is a question we get asked a lot here at Browns. Without knowing every detail about your house it's impossible to say what's best for you. So instead we've compacted it down to 4 common areas that most houses could improve on.


Before you start the house needs to be well kept. There's no point in injecting your cavity wall if there's holes in your roof. The same goes if your house has a damp problem, this needs to be fixed before you even think about insulation.

Make sure you consider the entire house when making improvements. Make sure there's sufficient ventilation throughout the house to stop the build up of damp.

1. Roof and loft

Lets start at the top. This is probably the most economical route of improving your insulation meaning it has the shortest pay off period. So much so that I've already written another article about this here, and highlighted some great products to consider.

New guidelines state that modern houses must have a minimum of 270mm of loft insulation between the rafters. This is the new standard and if you are building a house from scratch this is what they will ask for.

However if you've already got around 100-150mm of insulation then you probably don't need to worry about topping it up. Of course its always good to be meeting modern standards but the pay back time on something like this can be around 10 years.

Things to consider...

Don't forget to insulate the loft hatch, or the heat will still be escaping through this.

Don't block the eaves, these need to be left for ventilation to stop condensation. If you do block the eaves you'll go up to the loft and find it seems to be sweating.

If you've already converted the loft, any insulation will need to be added to the ceiling. If you don't want to lose any ceiling height a great alternative to PIR foam is Multifoil insulation. This also works as a vapour barrier.

2. Ground floor

If you've got a concrete floor, which a lot of houses do, this area is a no go. The best thing to do is get a good underlay to go underneath the carpet or wooden floor.

Even if you do have space underneath your floor boards like a suspended timber floor it is fraught with danger. DO NOT do what I saw on the news the other day and spray foam insulation in between the floor joists. Your house needs ventilation, Without it you get all sorts of problems like damp. You need to make sure your air bricks are left clear, if you don't then the joists can rot

3. Windows

Now if you've been in your home longer than 6 months and it's not a new build, you've definitely had someone try and sell you double glazing door to door. These PVC white windows are the standard these days and they have a great thermal efficiency as long as they are installed correctly.

If however you don't like the look of these white plastic boxes, there's still plenty of timber framed window options out there. You can even get a second pane of glass retrofitted. This means you get to keep the look of any character or traditional windows.

Be Warned

Don't get ripped off. If you already have double glazing fitted properly, you don't need new windows fitted. although current regulations will likely be a lot higher the cost of replacement more than outweighs this.


Depending on how old your house is, the external walls can be one of three ways. pre 1919 and the wall will likely be solid. pre 1975 and the external wall will have a cavity but won't be insulated. post 1975 and you'll have insulated cavity walls.

Solid walls can be insulated, but its tricky. Companies like Knauf do what they call a Thermoshell. This is an external insulation that covers the outside of the house. Perfect if you aren't concerned about the exterior look.

If you are you can insulate internally. The most common method I see is to use thermal plasterboards on the internal walls. There are other methods but these aren't as effective as it stops the wall itself storing heat like it should.

If you have an external cavity that's not insulated it's common these days to get it filled with a sprayed insulation. I've written an article just about this here.

However, you need to make sure you get a professional installer with this. In areas of high exposure this is unsuitable as the moisture from driven rain will use the insulation to travel into the actual masonry of the house, where it will rot joists and cause damp problems.

In summary

There are plenty of ways you can make your home more energy efficient with insulation, but these are not without risk. If you do decide you want to better insulate your home ALWAYS use a professional with a good reputation.

Written by Edward Parlato

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