I would like your suggestions/experience/opinions on designing steel windows+patio doors, using hollow sections (RHS as they call them) and angle sections. The window style I have in mind (but can not afford to buy and transport to my country) are the iconic Crittall windows.
Alas! Crittall use a special steel section which they manufacture themselves and I can not find in the market here. So I have to use steel sections which I can find in my country: angles, tees and hollow sections:
As far as aesthetics are concerned, my main worry is "thin sight-line", i.e. the frame to be thin, maybe a width of 30mm.
I have solved (i think) life-expectancy and maintenance issues as I intend to bath-galvanise them and then (optionally) powder paint them to give them a nice gloss color and life expectancy (maintenance free) of 20 years at least, if not 50!
The welding will be undertaken by a professional.
My main problem is air-tightness. It is easy to design on paper but in practice I do not know how efficient it will be.
Basically I follow the rule that when closed, the frame of a window should 'kiss'/'push against' the steel case (screwed on the wall) at two different places. Thus air trying to get inside the house must by-pass two obstacles/seals/weatherstrips.
I also intend to 'glue' (somehow, or even screw) on the steel frame rubber/insulation foam/seals (weatherstrip they call it) - something which aluminium and crittall windows do very well because their sections have been designed to have a channel where the rubber seal goes in and stays there without need of glue or screw. Glueing on metal is probably a nightmare.
The basic idea can be seen from these crittall drawings: http://www.crittall-windows.co.uk/wp-content/uploads/HOMELIGHT-DG-WEB-DOWNLOAD-11-15.pdf
There will be two types.
1) Opening out, 'casement' windows, height 2m, width of each pane 0.6m. They will be hinged on the sides, top and bottom. Here is a drawing of the side-section (i hope it makes sense):
2) Swivel or vertical pivot type. The hinges will be at the middle of the window frame, top+bottom. Sorry no drawing for this.
1) Do you have any comments/suggestions about the air-tightness of the design in the image attached?
2) Do you have any suggestions on how to implement the vertical pivot window type (using the same RHS, flat and angles as with the openout window) as far as air-tightness is concerned. Suggestions about the hinge?
3) From the drawing you can see a wooden frame at the inside of the window securing the glasspane against the exterior steel angle. This wood will be screwed onto the steel frame. What do you think as far as safety is concerned?
4) What is the best way to secure the weatherstrips/seals onto the metal frame?
1) glass will be double-glazed 5mm+18mm airgap+6mm, weighting about 30Kg/m2, so for a 2m x 0.6m window, the total weight will be 45Kg plus, say, 10Kg of steel=55Kg.
2) The windows will imitate the crittall look of horizontal splits every 30cm by using a one-piece glass pane and then welding on the outside thin pieces of metal horizontally.
I have given only an outline of the project, if you need clarification let me know.
thanking you in advance,