Secondary Glazing - Noise ?

Coniferman said:

Anyone any ideas what the void was that I drilled into??? I'm sure I don't have plasterboard so expected just plaster on block or do they frame around the internal of the window and plaster over???It was too close to the inside to be the cavity. Drill seemed to go quite a way in without resistance? Would be interesting to know as it may have an affect if I do any other windows and am also just curious?

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might be hollow concrete blocks. I have them (tri-wall with webs) as my interior leaf. The walls and and webs of the blocks are about an inch thick. The concrete is very dense and hard. Did the dust seem to be grey concrete? If you poke a bit of wire it in should reach the next web in about 6 inches.

JohnD said:

might be hollow concrete blocks. I have them (tri-wall with webs) as my interior leaf. The walls and and webs of the blocks are about an inch thick. The concrete is very dense and hard. Did the dust seem to be grey concrete? If you poke a bit of wire it in should reach the next web in about 6 inches.

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Yes!!! That could well be it. I did see some pictures of one when searching the net but it didn't seem to be something in common use. Would it fit with an early 80's build? Might try the poke wire trick.

I know from the past it is a grey dust. I also replaced a single mains socket for a double some time ago, in an external wall and it was VERY hard. Hammer chizel - sparks flying etc!!

Nice to know how these things work. Thanks for the info.

masona said:

You may have gone through the cavity wall gap, another way is to use a flat metal bracket with screw holes and screw it to the back of the frame then fix it to the outer wall cavity

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Thanks but it was only an inch or two from the inside of the wall.

if it is a hollow dense block, avoid trying to chisel it for an electrical box or a wallsafe. You may break away the outer wall of the block and have a big piece collapse inside.

I prefer to drill a lot of holes round the outline, and join them with a small, sharp narow bolster, working quite slowly. You may have to pack out the hole with rolled up newspaper then mortar as they are hollow and you need a good fit for the backbox.

If you're still having problem

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=77888&ts=68020

In case anyone is interested in a followup to this - the project is complete. It has make a noticeable difference to sound but I wouldn't say a massive amount, in my experience. As I am not in a particularly noisy area it may take a while before I know if it was worthwhile but I think it has achieved what I wanted.

Probably took 3 or 4 hours in total but as is typical with these things the instructions took some desciphering and if I had/have to do another it would be half that.

Because of the bigger gap I would say that aligning the jambs is less visually effective especially inside (because of looking at the window from an angle but the profile is small and it is hardly visible from outside. The finished result looks quite professional although the small stick on "handles" could be improved upon!!

oh and get several quotes for the glass - I was quoted between 45 and 300 for the glass alone !!!

I'm looking at secondary systems and wondered if you would recommend?