Aluminium double glazing and wooden frames for acoustic reasons?

gromituk

I was wandering along my street last night, knocking on doors and asking people where they had got their double glazing from if I liked the look of it, when one person told me he was ripping his out and replacing it with (white) aluminium units in hardwood frames, because they provided much better sound proofing than PVC units.

Is this plausible?

He was using hardwood rather than softwood for long life, but it got me thinking. The front of my house (on the street so noisiest) has the original wooden casements from 1926, the frames of which are perfectly sound (they used something not entirely unlike wood in those days). Why should I not keep the frames (two bays and a flat window), rather than the usual double glazing process of ripping it all out and putting reinforced plastic frames in instead? There would be slightly more maintenance, but it's north facing and I use high quality microporous paint so this wouldn't be a problem.

Any thoughts?

gromituk

Oh, he's also coming round this evening to look at my windows and possible other work he can do on my house.

alanobrien

gromituk wrote:

Oh, he's also coming round this evening to look at my windows and possible other work he can do on my house.

Interesting thread.

I suspect there is some truth in this as sound penetration through a solid object is at least partly related to its density and metal windows are obviously more dense than plastic.

Aluminium density = 2.64 g/cc
Upvc density = 1.4 g/cc

Not sure about the wood v UPVC frame issue, the density of hard wood
obviously varies and typically is around 0.5 g/cc.

I would be more concerned with the heat transfer properties myself and hence am looking at doing the exact opposite. i.e. Removing aluminium and replacing with UPVC. Then again i do not have any traffic noise issues to worry about.

gromituk

Ah yes good point - I know that older aluminium windows are not good thermally (I have a few and the frames are prone to condensation) but they are supposed to be properly designed now, with thermal breaks. I guess ones that conform to Part L of the building regs will have to be pretty decent.

I don't have a great deal of traffic noise - it's a residential road - but it's always nice to be in quieter surroundings if possible.

Rex_Mundi

Well I've got to say, in over 20 years in the glass trade I've never heard of changing frames to ally just for sound insulation.

I've worked on a few jobs over the years that required sound insulation. The main concern for us doing the job wasn't the frame so much, it was the type of unit and glass used. Triple glazing is the best way to kill sound. Even better if the unit uses different thickness glass. So you would have 4mm on the outside, 6mm in the centre and 4mm on the inside. I can't remember the specifics now, but it's something to do with the soundwaves hitting the different thicknesses of glass and being broken up.

It doesn't make sense to me to change the frame then put the same type of double glazed unit in. After all, the main area of a window is the glass.

The problem with triple glazing is the weight of the units. I've had to change hinges in the past to take the extra weight of triple glazing. This plus the extra cost (about double the price for the units) makes it a rarity to see.

gromituk

Thanks. I'm inclined to agree. And the guy didn't turn up last night anyway. Builders!!

gromituk

I guess it's possible, also, that the units he presently has are not sealing properly - I gather this is common with older externally-beaded systems. The gaps will let in sound as well as air.