How to minimise building certification & engineering fees

As an OB I am designing an extension on an old 1900s Jarah framed house. (now brick veneer)

I will replace the colonial hipped roof with a gabled roof and add a floor on top + dormers.

My question is, are there any guidelines to help minimise fees for certification and engineering sign offs.

I need engineer sign off on a retaining wall and the new roof will be pitched 45 degrees. Also, a new floor on top of existing jarrah frame.

At the moment, I am designing in Revit and will generate tables of windows, and also data for calculation of racking on roof envelope.

I am very limited on how much I can afford for engineering and certifcation so I am hoping to keep these fees to a minimum if possible.

Andre2018
The guidelines for engineering design certifications have tightened with the introduction of the Engineers Act in the eastern states.
BTW i usually have a chuckle, when designers & architects tell me what revit can do..Let me tell you what it can't do (as stated) , that is, check & certify the structure. It pretty much does everything else, quants, materials, dynamo, etc
Here's a Bim Summary
C Purlins for a loft floor
If you are on a tight budget you might want to consider truss frames for the attic
If you put your revit model up or leave a PM I'll take a quick look.
On a 45 deg pitched roof you also might want to consider a bay dormer window
Cheers
Chris

I much appreciate your reply.
I've confused you here. I want to build a liveable area in the Attic/Loft with a staircase ( I'm confused over Brit and US usage) so I assume I cannot use trusses.
I have budgetted for materials but not engineering sign off and building certification fees. That is a quantitiy I have no experience with.
I will need engineering sign off on a (1) retaining wall (1.5 metres high) (I am doing the design this week)
also sign off on (2) the second story loft. (45 degree pitch) gable dormers x 2, + 2 x shed dormers on opposing side of roof.
So I guess I will need to try to estimate this, and work out how much money to shuffle from materials/fittings funds.

I will look at the bay dormer window, thanks for the suggestion.
ATM I was thinking of 'wall dormers' flush with external brick skin and double doors opening inward. Just opened the loft floor example you linked to, thank you, nice example I will look at the details later.

Like most 'poor' OBs, I want to do as much work as possible on the design, I chose Revit, despite it being a little too complicated for me to learn quickly, (especially designing dormers etc) Then get my design vetted/modified/signed off.
The reviews I read, gave no recommendation of a simpler more intuitive substitute application.

regards,
Andre.

Try a simpler 3D Bim Program like sketchup



hth

The Engineers on this project
Formby Stairs
are worth every cent they were paid.......

Hi Chris,
re: your comment.
"On a 45 deg pitched roof you also might want to consider a bay dormer window
Cheers
Chris"

Can you post or link to an example bay dormer window.
Some sites indicate a "shed dormer" as a bay dormer, is that what you mean.
At present I am putting shed dormers on one side and Gable dormers on the more visible side to Laneway.
It occurred to me that you might mean a gable dormer that is set back from the wall plate, so windows or doors of the dormer are contained in a stepped in section, like a bay. This is in contrast to a wall dormer, where the window or doors of the dormer are flush with wall external wall below.

Andre2018





This is my favourite roof window detail
Cheers

Thanks. Does the height allow for a person to stand up, say about 170cm height ?

And how much cost is about ?

Thanks

Andre2018,

Not sure what your situation is regarding development consent/application approval/CDC etc but often the required sign offs are to fulfill the local building consent/construction conditions so required inspections may be quite variable within different councils. It may be worth talking to council what the required sign offs are for each element so the occupation cert. can be issued at completion which may be in addition to required engineering design certification.

In my area for example a 1.5m high retaining wall might need to be engineer designed an consent obtained via a DA which would require geotech investigation, structural design then geotech and structural inspection during construction so already a big cash difference.

No idea about specific structural inspections needed but request that the specifics are outlined in quotes. Quotes will likely be based on an hourly rate and not a set fee but you should be able to get a reasonable idea of times/requirements. Assuming no non-essential inspections are undertaken its normally the case that where the information required for sign off is easily observable/measured the cost is minimized- site delays/re-inspections can be a drain so knowing what is needed to be seen, and having it ready often reduces unnecessary costs.

Also bear in mind the travel time involved as it may be a similar rate to site time and often makes up the majority of the fees. Site sign offs are not done so much but you could also request sign off on site if the eng/certifier can do it. If you are paying for a senior/principal to come out, there is no real reason a simple site note in duplicate can't be done on simple elements rather than writing a letter after the inspection in the office. It can make a significant difference to chargeable hours.