Cavity Wall Insulation Question

[PaulM-S]

My late 1990s built detached house is not very warm.

On checking the external walls, the tell-tale signs of cavity wall insulation are visible on three sides of the property, but only for a small area towards the front of the house on the fourth side.

The side of the house that does not appear to have cavity wall insulation is the external wall of an internal garage and dining room down stairs and two bedrooms upstairs.

Just wondering if anyone has seen anything similar and have any suggestions.

 

[23vc]

How are you identifying the signs of it being installed from the outside? If late 90s it should have it when built rather than retro fitted?

 

[robinbanks]

My late 1990s built detached house is not very warm.

First consider draughts from gaps and holes in the fabric of the building; this vintage should have insulation built in. A blower door test could be good to identify where your paid-for warm air escapes. Infrared cameras at night, cold outside, heating on and be another good diagnostic but be sure you understand how to interpret the images

Is the garage door insulated?


Can you find a relatively low impact way of looking into the cavity? Remove an extractor fan or upstairs windowsill etc

 

[^woody^]

How are you identifying the signs of it being installed from the outside? If late 90s it should have it when built rather than retro fitted?

Some builders used a post-build blown in system on their developments, others may have used insulating blocks and relied on a whole house u-value calculation which did not require additional wall insulation.

All retro fit installs should be recorded via a building regs notification.

 

[^woody^]

Have you lived there from new? Were the walls insulated retrospectively before you purchased?

 

[PaulM-S]

Thanks for the responses.

A bit more info:

I've identified that cavity wall insulation has been installed on three sides as there are tell-tale drill marks on the outside that have been filled with matching mortar.

The EPC for the property says 'Cavity Wall, Filled Cavity'.

One thing I should have mentioned is that the internal garage has been converted to an additional room with no insulation in the walls and polystyrene in the floor. This is the coldest room in the house.

I've checked the local councils building control portal for any building regs notification for the property and there's nothing recorded for retro fit of cavity wall insulation.

I haven't lived in the property from new, but I lived in another property on the same estate from 2016 which was built at the same time as my current property - late 1990s. This did not have cavity wall insulation on purchase but was installed in 2018 via a free government scheme and was registered via a building regs notification.

 

[endecotp]

My late 1990s built detached house is not very warm.

Is there heating? If so, what is the thermostat set to? Does it reach that temperature?

 

[^woody^]

With the retro-fit market, and particularly grant funded schemes, the installers were under pressure to complete several properties per day and it was common for installs to be done very quickly and haphazardly, with some areas missed completely.

Either have a thermagrahic survey done, or get hold of a thermal camera yourself and check the situation. If you do this yourself, don't get too hung up on the images as interpretation is everything, just look for significant differences in the external walls. Do this at night when dark.

 

[PaulM-S]

Thanks for the additional responses.

There is heating and the thermostat is usually set to 20. The house does eventually reach this temperature but downstairs still feels cold. However, the converted garage never reaches this temperature and is always about 3 degrees below what the thermostat is set to.

Thanks for the info about haphazard installs. I wonder if I've been a victim of this.

I've had a chat to the neighbours and they've said that a lot of houses on the street were insulated through a government scheme which was promoted abot 10 years ago. Looking on the planning portal I can see that a lot of houses on my street were insulated in late 2011 / early 2012 as they've got building reg notifications.

 

[endecotp]

There is heating and the thermostat is usually set to 20. The house does eventually reach this temperature but downstairs still feels cold.

If it is actually warm yet feels cold to you, you need to understand why. Could it be draughts? Or something to do with humidity? Or maybe you have e.g. tiles on the floor, rather than carpet, that feel colder underfoot? Maybe the thermostat is too near a radiator so it's not measuring the real room temperature? I don't think you can say there is something wrong with the insulation or the heating system if you set the thermostat to 20 and it does reach that temperature.

However, the converted garage never reaches this temperature and is always about 3 degrees below what the thermostat is set to.

Right, it's quite likely that the conversion not been insulated sufficiently. You should investigate the structure of the walls and floor. But that's separate from the main house.

I've had a chat to the neighbours and they've said that a lot of houses on the street were insulated through a government scheme which was promoted abot 10 years ago. Looking on the planning portal I can see that a lot of houses on my street were insulated in late 2011 / early 2012 as they've got building reg notifications.

But not yours?

I'm surprised that a house built in the late 90s would have had such poor insulation installed at that time that it would be eligible for a scheme in 2011/2012. Are you sure that it's not earlier than the 90s? The only 90s property I ever lived in was so well insulated that I hardly needed to have any heating on at all, except in the depths of winter!

Woody's advice to get a thermal camera is a good idea, and you should do it soon while it's still cold outside.

 

[PaulM-S]

If it is actually warm yet feels cold to you, you need to understand why. Could it be draughts? Or something to do with humidity? Or maybe you have e.g. tiles on the floor, rather than carpet, that feel colder underfoot? Maybe the thermostat is too near a radiator so it's not measuring the real room temperature? I don't think you can say there is something wrong with the insulation or the heating system if you set the thermostat to 20 and it does reach that temperature.



Right, it's quite likely that the conversion not been insulated sufficiently. You should investigate the structure of the walls and floor. But that's separate from the main house.



But not yours?

I'm surprised that a house built in the late 90s would have had such poor insulation installed at that time that it would be eligible for a scheme in 2011/2012. Are you sure that it's not earlier than the 90s? The only 90s property I ever lived in was so well insulated that I hardly needed to have any heating on at all, except in the depths of winter!

Woody's advice to get a thermal camera is a good idea, and you should do it soon while it's still cold outside.

Thanks for the response and all very good points.

We're definitely investigating draughts and humidity. There is wooden flooring throughout the downstairs of the property, which was installed by the previous owner. The smart thermostat is in the main hall and is a reasonable distance from a radiator but could be having an affect.

The garage conversion is definitely being investigated as it is the coldest room in the house and the lack of insulation is hopefully going to be rectified.

I've checked the deeds for the house and it was built in 1998, similar to the previous house I lived in on the same estate and neither had insulation. Also, spoke to the neighbours who've lived in their house since it was first built and they purchased in 1998.

We're definitely going to take up Woody's advice to get a thermal camera.

I suspect that it's not one thing that is causing the general feeling of coldness in the property, but a combination of a number of them which when rectified will sort the issue.

 

[endecotp]

I've checked the deeds for the house and it was built in 1998, similar to the previous house I lived in on the same estate and neither had insulation.

Here's a table from https://www.ecomerchant.co.uk/news/a-brief-history-of-building-regulation-u-values-with-examples/ :

I find it hard to believe that there is no insulation in your walls. An uninsulated cavity wall will have a U-value worse than 0.6.

 

[robinbanks]

There may be no insulation in the cavity; it isn't the only place walls are insulated. Or there may be no insulation due to a build error. Inspections aren't carried out on every house; on large sites with many houses of the same model a representative sample of each will be tested for compliance and the assumption is they've all been built the same

Woody's advice to get a thermal camera..

..is useful, and wasn't the first mention of it either

 

[robinbanks]

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