New Build Floor Structure

[GazzaS]

Hi,

Last year I completely some wiring of AV equipment on my new build house. Most of this wiring involved using access holes in the floor boards to pass cables underneath (see first picture below). Part of this involved creating small holes through chipboard that linked the joists together.

At the time I asked a builder on site if making holes in the wood was ok. He stated that the load bearing part was the joists and that the chipboard between was not load bearing and was to insulate against noise and heat loss. I also observed that the builders themselves had made several holes through this wood (see picture below).

Today I posted some pictures and summary of the work I had done and another user commented was drilling through this wood correct. This rang alarm bells and therefore I just wanted to check with everyone if making small holes to pass cable though in the chipboard wood between joists was ok?

Thanks for any comments.

Gary

Access Holes:
View media item 30655
Existing Holes From Builders:
View media item 30661

 

[Static]

See page 11:
http://www.kentinternational.ca/brochures/Timberframe_System/TJI.pdf

 

[GazzaS]

Hi Static,

Thanks for the reference it was very helpful. I also did some research and have learnt that perhaps talking to a random builder on site was not the best thing to do

So basically the joists were I-joists, two Flanges separated by a web of chipboard. The whole thing is load bearing and the web helps insulate against heat loss, fire and noise (at least he was right about something). According to the manufacturer you are able to cut small (and sometimes large) holes in the web as long as minimum distances away from bearing points and other holes are met.

Luckily the holes I made were mostly the size of a speaker cable (5-10mm) and maximum one was about 20mm (under an inch). I also copied what was already there by making sure the holes where round, were in the middle of the web and did not occur near other holes or support.

Thanks again,
Gary