Combinations roof window install (Fakro)

tonydude

Hi , looking for some structural advice for the install of a double combination roof window.

I'm mostly focused on the vertical upright post that's going to take the weight of the double rafter coming down between the 2 windows. Whats the best way to do this. It's block built with a 200mm cavity and I've currently just joisted it. The post can be no bigger than 100mm wide to accommodate flashings. I've added a pic of a different job,where the inner leaf is studded out.

My thoughts are shutter where the post should be located and bed an galvanized T anchor into get, letting it about 300mm proud. Then sandwich two 6x2s around it.

Any thoughts would be appreciated 👍

DOCARCH

Mod Note: Just to note the forum charter - Section 1.5

Structural items . Issues relating to the specification of structural components is prohibited. Any queries in this regard need to be dealt with by an architect/engineer privately.

Best to consult a structural engineer with your query.

C. Eastwood

https://www.boards.ie/discussion/2058257318/combinations-roof-window-install-fakro

You could also consult a Chartered Building Surveyor or Registered Builder Surveyor or a Chartered Civil Engineer

DOCARCH

https://www.boards.ie/discussion/comment/119425741#Comment_119425741

Sorry, but that's like going to the doctor with a toothache!

A building surveyor certainly may be able to advise, but it's a structural engineer that's required (to calculate, detail and specify).

C. Eastwood

https://www.boards.ie/discussion/comment/119426511#Comment_119426511

What an insult to Chartered Civil Engineers.

DOCARCH

Good to know it's not an insult to building surveyors! 😀

A structural engineer is the required professional.

C. Eastwood

A second year Civil Engineering student could design the supports for the 3 roof windows above.

DOCARCH

https://www.boards.ie/discussion/comment/119426631#Comment_119426631

I have no doubt they could but could they sign off on it, provide an opinion on compliance and have the PI insurance to back it up?

Stone Deaf 4evr

https://www.boards.ie/discussion/comment/119426631#Comment_119426631

indeed and they could in theory, but personally, id rather have someone with some paperwork behind them and real world experience / insurance behind them to do it, rather than some 'have a go' hero.

C. Eastwood

A Chartered Civil Engineer with PI Insurance could design and furnish a Certificate of Compliance.

They are capable of designing the support of the 3 roof windows above after completing 2 year Civil Engineering of a 4 yr Degree.

It is therefore axiomatic that after they graduate and obtain the CEng title after another minimum 5 years, they would still be capable of designing the support for the 3 roof windows above.

muffler

https://www.boards.ie/discussion/comment/119426711#Comment_119426711

Let's go back to your claim about a 2nd year engineering student doing the dedign. Can he or she stand over it and inspect and certify as asked by DOCARCH?

muffler

https://www.boards.ie/discussion/comment/119426519#Comment_119426519

You got that spectacularly wrong. Nothing new there I suppose.

C. Eastwood

https://www.boards.ie/discussion/2058257318/combinations-roof-window-install-fakro

tonydude

You should retain either a Civil Engineer or a Structural Engineer to design the structural support for the 3 windows in the roof.

chooseusername

https://www.boards.ie/discussion/comment/119431574#Comment_119431574

You should retain either a Civil Engineer or a Structural Engineer to design the structural support for the 3 windows in the roof.

If they're going to retain an Engineer why advise them to consult a Surveyor?

"You could also consult a Chartered Building Surveyor or Registered Builder Surveyor or a Chartered Civil Engineer

C. Eastwood

https://www.boards.ie/discussion/comment/119432145#Comment_119432145

I am delighted to be able to provide you with more advice

Some Civil Engineers and some Structural Engineers may decide to act only as Ancillary Certifiers:-

4.2.2 Ancillary Certifiers

Apart from the Assigned Certifier and Design Certifier there is likely to be a range of certifiers on most projects, including certifiers appointed by the Building Owner, by his design team and/or by the Builder. 

Therefore the Building Owner may have retained one of the following as a Design Certifiers and an Assigned Certifier:-

Chartered Building Surveyor or a Registered Building Surveyor or a Chartered Building Engineer or an Architect.

The Assigned Certifier could retain an Auxiliary Certifier to design the steel structure.

It’s what most Building Owners do.

DOCARCH

https://www.boards.ie/discussion/comment/119433046#Comment_119433046

🤔😥🤐 Going a bit OT there!!!

What's Design Certifiers and Assigned Certifiers got to do with it?

Back to basics, the OP needs to engage a structural engineer.

C. Eastwood

https://www.boards.ie/discussion/comment/119433327#Comment_119433327

Try and read all of the comments, and try and read each comment fully, when you intend to reply to a comment which answered a previous comment

chooseusername

Registered Users

Posts: 1,771 ✭✭✭ 05-08-2022 10:30am

C. Eastwood9:26 am

https://www.boards.ie/discussion/2058257318/combinations-roof-window-install-fakro

tonydude 

You should retain either a Civil Engineer or a Structural Engineer to design the structural support for the 3 windows in the roof.

You should retain either a Civil Engineer or a Structural Engineer to design the structural support for the 3 windows in the roof.

If they're going to retain an Engineer why advise them to consult a Surveyor?

"You could also consult a Chartered Building Surveyor or Registered Builder Surveyor or a Chartered Civil Engineer

chooseusername

https://www.boards.ie/discussion/comment/119433046#Comment_119433046

Thanks for that advice, it's been filed away.

In post 13 you said,

"You should retain either a Civil Engineer or a Structural Engineer to design the structural support for the 3 windows in the roof."

(No mention of Surveyors here)

Now, not all Civil Engineers are Structural Engineers, as you know, so the best advice to the OP is to consult a Structural Engineer.

Funnily enough that was the advice in the very first reply by @DOCARCH, and it should have been all over. ( It is now, for me anyway)

muffler

Sometimes people dig themselves so far into a hole that they need a CHARTERED structural engineer to design a bespoke ladder to get them out of it!

tonydude

Hi guys, the end result will have a double rafter and a double 9x2 as the post. Steel will be sandwiched in-between. Steel will be fixed into a cast top block and go up the post and follow the pitch of the roof for about 3 feet. 👍