Another topic and question. As many you have seen from my past posts, we are building a multi story concrete home. ICFs and Hambro floor system. I will sending my DWGs to the ICF block and Hambro manufactures soon. They will make their sizing reccomendations on their materials. How critical is it to have the project reviewed by a structural engineer? What should I expect to pay?

I will expect the ICF block and Hambro guys will have speced the products prety well. I also understand they themselves will not 'stamp' their work. What do you guys think?

Patrick T

Depending on where you live, you will have to have an engineer review your design. He will make suggestions on rebar sizes, spacing, lentel tables for windows, footers sizes etc. I ended up paying around 30 cents per square foot for the engineer to do the work in northwest florida. I would highly reccommend getting who ever is going to install your walls into the conversations with the engineer. He can make resonable suggestions to the engineer. If not, more than likely, you will end up with plans that will include things that are not revelant to your design. This happened to me. When the inpector comes out to look, your house has to match the design, if not, they ask questions. So its always a good idea to get everything right the first time.

I seem to recall that Hambro already has their product specified for specific distances and loads, already checked by their engineers. This is part of their service.

As to the ICF mfg "stamping" their product, this too is pretty much in the past as there are now specifications built into the IRC codes providing specs to build for typical structures. In the event of really different or structural quirks, you may require additional engineering. Sometimes the mfg can help, other times you hire am outside source!

Also, I believe that the Prescriptive Guide for ICF Construction, 2ed, may answer many questions. But I agree having an OK from an engineer may make for easier sleeping, JMHO. Good luck with the project.

Using an engineer for easier sleeping is a redundant step in the building process when specific ways and means, such as the Prescriptive methods AND specific code requirements are already present.

However, if anyone does not understand the procedures and methods and requirements, then by all means use every source available in order to build safely! It is important that you do things correctly, and misunderstanding something can be very troubling.

It is also important to know "when to say when" and then engage those professionals, such as a PE, in order to build to standards that are safe!

Patrick,

Jim is right, you will sleep better. A good engineer will save you more than the amount of his fee in materials, time, and possible delays by the county who may not understand the process. The only thing that concerns me in the description of your design is the I-Joist system for your choice of floors. I-Joists are notorious for having a "bounce" to them if they are not looked at properly by an engineer familiar with the product. And I am not talking about the manufacturer's engineers either, for their paycheck is directly linked to you buying their system. I-Joists are a great system just not the answer for every floor. I am involved in the remediation of a building with an I-Joist system that we will be going in to try and dampen the bounce of the floor. This is a costly and time consuming endeavor. So it is time and money well spent to have an engineer versed in the types of construction materials you are using to examine your plans before you submit them to the county, city, or whomever.

ICF Contractor

ICF Contractor,

I have heard that composite floor systems may have bounce if spec at min spans. I have a 28-29' span that I will likely bump up to the next size/depth that is reccomended by my supplier.

How do you 'dampen' bounce in a floor other than adding a wall/beam underside? Does look like you have a costly project. Good luck

Patrick T

Patrick,

What will happen to this building is we are going to add to the dead load on the floor by about 15 psf. The safety factor on this specific floor allows us to add to the dead load. Bumping up to the next size or depth may not effect your bounce issue. The bouce is caused by a harmonic resonance and you would have to look at the design and spans to see how it would be affected.

ICF Contractor