solid glass blocks vs hollow glass blocks

Hi everybody..i'm finishing my design( http://www.johnlsayers.com/phpBB2/viewtopic.php?t=8898 ) and i have another question for all you great people :) i really want to keep daylight coming in my semi basement studio but i'm really concerned about lowering the overall STC of my room in a room structure with a glass window(well 2 windows) plus the high cost of a really good laminated glass system.....oh and privacy is another thing...the studio is located in a central street and having windows at ground level is not that nice for recording musicians So i was thinking of replacing windows with glass blocs,,,what do you think of it? i found one related topic in this forum but i didn't really reach a conclusion :oops: Also ...should i use the standard hollow blocks or i must go for the solid(and very expensive) ones? i mean if i put hollow blocks on both sides of my 2 leaf wall i actually create a 4 leaf wall or not? and finally does a 2 leaf wall with solid glass block windows have a higher STC than the same wall with a dual framed laminated glass window on it? well i think i really need your help on that.... Nikodemos

please guys...any info on glass blocks (solid vs hollow) will be very very much appreciated :? thnx Nikodemos

Nikodemos, I superficially checked that other thread. It's a bit unclear to me what these double walls you talk about exactly look like. Hence, just general: double glass blocks will not behave as a 4 leaf wall. These blocks act roughly as a single leaf. The same goes for hollow bricks and hollow concrete blocks. Hence you can use them. Their TL can roughly be estimated in function of their mass. Hence solid blocks are better. Whether you need them or not, needs more exact details from your side. But since I still don't exactly understand that wall build-up ....... I can't very well imagine that you integrate glass blocks in a gypsum board leaf. But you also can combine glass blocks and a window pane as a second leaf. Note that glass blocks more behave as bricks than as a flexible panel as drywall (relates to isolating above or below coincidence). If you explain your combination better it easier to get the feel.

first of all Mr. Desart thank you for your interest :D As i understand you are saying that i could go for a compi of a glass block window on the outter concrete wall and a glass one on the inner drywall as in the jpg...right? i think that it is possible to put a glass block window on drywall steel studs but i don't know how possible it would be to seal it properly...so the combi might be a better idea...what would you think would be the best way to keep the daylight coming in in a very noice concerned situation like a rehearsall room? do you think the glass block- laminated glass combi(jpg) would have superior TL ratio over a normall double window with laminated glasses of that size or i'm in a copletelly wrong path here? please if you find sometime please let me know about my project thanks again Nikodemos

Nikodemus. Your drawing looks perfect. What I should do is using the solid glass blocks to compensate for the loss in mass versus the concrete wall. Glass ca 2500 kg/m3. Concrete depends on mix, but say very roughly 2200 kg/m3. You compensate that somewhat already by your larger cavity, but not enough. Hence get the most of it by using solid glass blocks. Your laminated glass inside fits the mass of the drywall, which is OK too. It should have no sense here to combine heavy glass blocks in these drywall leafs. I couldn't make a better design. Now you have to find something to close that gap between inner and outer glass visibly with something that does not connect inner and outer wall. You of course can use non-transparent lamited glass on the inside as well, but still it's better that no dust can nest itself between these panes. And use something acoustic transparent as e.g. fabric. It's good that there is an acoustic shortcut between the cavity behind the drywall and the cavity between the glass. As such the cavity behind the drywall will act as edge absorption for the panes. Always note that hygrothermal conditions can cause trouble for moist, but that's for a lot of cases (also drywall) where is sinned against basic principles of a damp screen at the hot side.

thanx for your reply mr. Desart.....it was really helpfull :D would it be ok to post a drawing of my wall and floor design for you to check and tell me what you think? please let me know and i'll post it on this thread asap. thanx again Nikodemos