Cavity wall insulation grant

whatsthenews

Hi,
applied to be considered for a grant for cavity wall insulation and our energy provider Octopus contacted us to say we qualify and requested we complete a form.
At the very beginning there's an info video about condensation in the home . Immediately after that it asks that you agree to having trickle vents added to windows and wall extractor fans fitted in bathrooms and kitchens. It says the work is required in 95% of properties.
Not worried about the extractors as we have one in the bathroom and kitchen, however I'm not at all keen on having trickle vents added because a) they're ugly b) the windows are brand new c) the one's I've come across create a cold draught!
I don't have the online form open ATM but they seem to suggest this is a government regulation.
I''m not sure I understand why having CWI fitted wthiould increase the risk of condensation, in fact I thought it would reduce the risk of condensation on colder external walls. 
The only time we have any condensation in the house is in the bathroom after a shower and we use the extractor and open the window and very, very occasionally in the kitchen and we do the same. Tumble dryer is a condenser in the garage and we never dry clothes in the house. 
Maybe its a ploy to stop people taking up the grants?
If I contacted a company directly I wonder if they'd say the same ? Must be a relatively new thing as we had CWI done 3 years ago in our last house.

whatsthenews

https://dysonenergyservices.co.uk/new-ventilation-requirements-and-cavity-wall-insulation-what-householders-need-to-know/
Madness. If I'm stupid enough not  to open a window then I'm not going to open a trickle vent either.
10mm gap at the bottom of all internal doors? 

stuart45

The reason that condensation might be an issue is that CWI makes the house more air tight, so a slight increase in ventilation is often required. Having a 10mm gap under the internal doors has been found to help.

FreeBear

whatsthenews said: At the very beginning there's an info video about condensation in the home . Immediately after that it asks that you agree to having trickle vents added to windows and wall extractor fans fitted in bathrooms and kitchens. It says the work is required in 95% of properties.
Not worried about the extractors as we have one in the bathroom and kitchen, however I'm not at all keen on having trickle vents added because a) they're ugly b) the windows are brand new c) the one's I've come across create a cold draught!

Part F of the building regulations requires a certain amount of background ventilation when certain thermal upgrades are carried out. Nowhere in the documents are trickle vents mandated - It even goes as far as to say alternatives are acceptable. However, certain sectors of the building industry have twisted the wording to say that you must have trickle vents. If you examine Part F closely, it says should rather than must, so not mandatory.

If you have a PIV or MHRV system, that should satisfy the background ventilation requirement.

twopenny

Each property will be different depending on the building and the people occupying it.

I had the insulation in my last property, brick, single glazed with south facing wall but got a lot of warmth from the sun when it was out.

The wall insulation meant that it stayed warmer when the heating was on - but remained colder on days in spring and autumn when the heating was off and sun out. So I had to use the heating for longer.

Ditto the attic once insulated things stored there started to get mildew because there was no heat from the house.

More rooves have moss or lichen, the snow doesn't melt because of the insulation.

Very old buildings (17thC) with insulation I've known have condensation.

Neighbours 2000 house is dry as a bone.

So it's horses for courses.

Chickereeeee

I had CWI  done last year. I had 'surveys' done for both government-funded installation, and privately-funded. Neither required, or mentioned trickle vents. Gaps under doors were looked at, extractor fans were asked about (not checked). I went with the privately-funded installation, for various reasons.

Beeblebr0x

The thing that puts me off government schemes is not being able to choose who does the work

Chickereeeee

Beeblebr0x said:

The thing that puts me off government schemes is not being able to choose who does the work

That's one of the things that put me off. There seemed to be a chain of companies, from a local one (S England) that the council liaised with, through  a larger one in South Wales, from which telephone calls  came, to the company which actually did the work - whom I had never heard of.

whatsthenews

stuart45 said:

The reason that condensation might be an issue is that CWI makes the house more air tight, so a slight increase in ventilation is often required. Having a 10mm gap under the internal doors has been found to help.

does CWI make the building more airtight? I thought it just reduced heat loss (and gain) through the cavity. 

whatsthenews

Beeblebr0x said:

The thing that puts me off government schemes is not being able to choose who does the work

Mmm- I've thought about that too. 

whatsthenews

FreeBear said:

whatsthenews said: At the very beginning there's an info video about condensation in the home . Immediately after that it asks that you agree to having trickle vents added to windows and wall extractor fans fitted in bathrooms and kitchens. It says the work is required in 95% of properties.
Not worried about the extractors as we have one in the bathroom and kitchen, however I'm not at all keen on having trickle vents added because a) they're ugly b) the windows are brand new c) the one's I've come across create a cold draught!

Part F of the building regulations requires a certain amount of background ventilation when certain thermal upgrades are carried out. Nowhere in the documents are trickle vents mandated - It even goes as far as to say alternatives are acceptable. However, certain sectors of the building industry have twisted the wording to say that you must have trickle vents. If you examine Part F closely, it says should rather than must, so not mandatory.

If you have a PIV or MHRV system, that should satisfy the background ventilation requirement.

Sorry but what's PIV please? We don't have MHRV. 
I really don't want trickle vents. Might  just see if I can find a company and get a quote.
It's only really the bedroom that as 2 outside walls that feels cold. We discovered that underneath ground to roof UPVC cladding there was no cavity just a single skin so had that made into a cavity with insulation. That was on the front between the 2 windows. Underneath the bedroom in question's window there was also UPVC cladding so we did the same there. It's the other wall that feels really cold.. Bedroom gets toasty when the heating is on but cools down much more quickly than other rooms.