Cavity wall insulation

[True blue]

I recently had cavity wall insulation and the bloke doing it has blocked up the air vents in the wall with silicon. He said this was necessary to get the best from cavity insulation . I think these air vents should be open . is this right or is it ok because of the cavity wall insulation ?

[carrust]

If the air-vents are below the damp-proof course you should get them un-blocked immediately !!!!

[gasman]

As above but also there may be an air vent for your boiler or gas fire !!! in which case he wants reporting and could have put your life in danger. The air vents should have a liner in them so the cavity insulation wouldnt make a difference anyway if they were blocked up or not. So he is talking out of his rear end.
I suggest you get a second oppinion.

[jake-the-peg]

gasman has alluded to this but let me reinforce it.

If you have any gas appliances in the house they need ventillation BY LAW!

If they are inadequately ventillated they are dangerous - Note that if a gas engineer finds this to be the case and cannot clear the vents he will disconnect your gas appliances for your own protection this is how seriously this is taken.

I would also advise getting a second opinion. In the meantime get a corbon monoxide alarm from your local DIY store - this should tell you that your house is safe enough while you get a second opinion

[gasman]

Let me tell you that i was once asked by the fire department to check out a gas fire that had caused a HOUSE FIRE !!!. Upon investigation i found a blocked air vent. And that made the flue inopperative so instead of the flue pulling or sucking the products of combustion safley out of the building it caused the reverse & blew the fumes & naked flames back into the house !!! And all because of a simple thing like a blocked air vent.

[True blue]

tks for yr replies. very interesting .
I will remove the silicon myself , once again tks.