This thread has been split off from the Encouraging the next generation of model boaters thread.

Colin

David, I think a few years ago I would have tended to agree with you but more recently I get the feeling that the computer is doing too much of the thinking for us. This was emphatically proved to us only this last year.

Interesting story.

We decided to have a glazed conservatory roof replaced with a solid tiled one and so eventually settled on a local firm to do the job. Because of the tiled covering the new roof had to be of a slightly steeper pitch than the old lean to glazed roof so we had to have an apex. I decided for a few reasons that the apex would be best moving towards the house and the ends were going to be glazed gables.

The old roof came off and the apex was supported by acro props under the apex while the new longitudinal beams and rafters were assembled. Outside was skinned and insulated plasterboard was fitted internally until such point as the last acro prop had to be removed. As the prop was lowered the apex settled with it until such point as the main vertical windows started to lean outwards. It made sense to me as there was no transverse brace holding the rafters from settling and moving outwards. It looked to me like a major design flaw. I asked to speak to the company who manufactured the roof, asking for drawings and calculations, but was told that the ‘designer’ was on holiday for two weeks and he was the only one who could discus the job with me. I stopped the job and started discussing with various local structural engineers, discussing various remedial options such as cross braces or pillars under the apex. It was the worst two weeks I can ever remember going through as we realised the design was faulty and the whole lot could fall down. Even bringing the house wall down with it.

When I eventually got to speak with the designer I again asked to see calculations, drawings and designs but I eventually realised that there were none. The ’designer’ simply puts the dimensions into his computer program, supplied by the roof supplier, and it automatically churns out a parts list for him. He has no input as regards calculations, he does not evaluate the structure from a stress and strain aspect or any other, what I would expect to be, normal design process. The computer program does it all. What I also learned from this conversation was the fact that the design incorporated three transverse wires, which were specifically there to resist the movement we had seen. These wires were missed out of the kit of parts and no one in the subsequent process decided to question this. When I asked what tension was expected in the wires, he had no idea, when I asked what the maximum loading the wires could take, he had no idea and when I asked what loading would be placed on the house bricks by the wire anchors, he had no idea. He assured me that the program took into account the fact that the wall had been built to current building regulations and was of suitable strength. I informed him that the bricks were reclaimed and of around 200 years old and of very inconsistent strength. I asked for an additional wire to take 33% of the load off the wires. Despite this when one was being tensioned the anchor simply pulled out of the brick and needed moving.

What it left me with, apart from the trauma of thinking the house was going to fall down, was the fact that there is almost no knowledge required by the ‘designer’ nowadays when such structures are designed. The only person involved in calculations is the original software designer and he has no clue whatsoever when it comes to real life challenges and things that do not match the ‘norm’. To me this is a scary direction to take but, as always, driven by cost and therefore attractive to the business.

Edited By Colin Bishop on 30/12/2022 10:19:15

Colin, they reckon the weight of the tiled roof is comparable with the weight of the original glass. The tiles are plastic of course and the beams and rafters are all aluminium.

Taking light from the house interior was one concern but as the original leaked like a sieve and then, one day, a glass panel simply exploded we had to do something. We could have had a couple of Velux units but decided they would be more trouble than they would be worth. It has transformed the place and given us a whole new space but I check the wire anchors every morning to see if they have moved!

Edited By Colin Bishop on 30/12/2022 10:10:53

Hi Richard,

What a magnificent conservatory ! just looking at your window boards gave me an idea for a 009 narrow gauge end to end line in my conservatory

Thanks I have the sketch book out already !!

Regards & Happy New Year

Ray

Edited By Colin Bishop on 30/12/2022 10:13:29

Now there is an interesting idea. Not sure I would get that past the authorities though!

Happy New Year to you as well Ray, stay safe.

Edited By Colin Bishop on 30/12/2022 10:12:58

I fully agree Colin and, as one of the last generations to be taught how to use a slide rule at school, it has always been my own thought process when dealing with a challenge. The problem with a lot of computer software nowadays is that you can put rubbish in and get rubbish out but too many people don't realise it is rubbish because they didn't know what to expect!