F5 instead of MGP10

Hi, my builder due to the timber unavailability used F5 timber for framing whereas the engineering specification was MGP10. When I found numerous holes in the studs which are above the standard of 250mm. The builder has offered to laminate where the holes are with another stud next to it. Is this reasonable? Do I have any other option?

Annoux

I would recommend you talking to your structural engineer just to be sure, but F5-F7 is standard in residential construction.

Also by laminating I am assuming he is going to install a second stud and attach it ( laminate it) by nailing the new stud to the original stud, which will make it a lot stronger and therefore is a very good solution.This is typically done where the stud needs to carry extra load from above, and you can laminate 2, 3 and sometimes 4 studs together.

Just double check all that with your structural engineer to make sure he is happy as well.

good luck

Simeon

Thank you so much for the advise Simeon. Getting it checked again by the surveyors. I have had my builder told me that they tell the engineers what to use. I was surprised to hear that as I was always under the impression that the engineers are qualified to decide on these things not the builders. It seems like the engineers work for the builders to reduce the costs unfortunately

need to get your engineer approval or use AS1684 span tables to check. Mpg10 can substitute for f5 not other way around. Probably will be fine but should not have been done. Pretty basic issue to mess up.

Happy Friday Annoux

I think you are going to find that MGP 10 closer aligned to F7, but you shouldn't be making any changes to your structure with out the engineer signing off on it first, as I dont think you can do a direct swap back from an F grade to a MGP grade.

There might be some additional strengthening needed, more lamination at load points etc. Im not the timber expert so I could be totally wrong


cheers

Simeon

Hope you've enjoyed the weekend freedom after so long. Your advise meant a lot.

Hey Annunox
The certified engineering details are for MGP10 ( a higher stress grade timber) , the builder will have to go back to their engineers to recertify the engineering for F5
Their Building surveyor is talking nonsense as they aren't licenced to change the original engineering Details without resubmitting new engineering
Also sounds like the builders doesn't want to pay the engineer, who knows what you'll get in the way of F5 grade, most of the timber I'm seeing are Dog house timber -> snook salmon-> john west reject (humour) .... Stand firm that's his problem
Sorry for posting here, but PMs don't assist others in a similar position
cheers
Chris

Thanks heaps Chris. I'll insist to get the engineering updated and see how it goes.

As mentioned if the construction complies with as1684 then the builder can use this. The correct paperwork must be submitted, whether it be an engineers report or referral to As1684. Now what you didn't mention was were the stud centers different? or was the timber a different size. Either way evidence to show that the design complies with as1684 is what you will need.

Hi Ardo, I am not from construction background. No idea what you mean by different stud centers. I probably can check the timber size. Is checking the span tables something that I can do? What do you mean by referral to AS1684? Is it same as the span tables?

As1684 is the residential standard for framed construction. It has information about the sizes and grades of timber that can be used and in what application. Studs are the main construction of the timber in walls. They support the load from the top plate to the bottom plate. Typical materials are f7 or mgp10 90mm x 35mm in size. The 'centers' are the distance between the centers of the studs or even the pitch if that makes better sense.

Lots of videos on YouTube about frames. Also a series on as1684!
https://youtu.be/2cszaf5IM3s

Thanks Ardo. Will check out