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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Carpentry Questions >> joist---Drilling & Notching https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1101309824 Message started by nyck on Nov 24^th, 2004, 3:23pm

Title: joist---Drilling & Notching
Post by nyck on Nov 24^th, 2004, 3:23pm

What are the rules/guidelines for drilling + notching out joists.
The joist are 175mm/7" & 2900mm long

Notch
15mm copper flow+return

drill
15mm speedfit flow/return
2x 2.5mm cable
1x 1.5mm cable

I havent decide if to use plastic or copper thats why i've asked for both.
When notching is it best to1 larger notch for the flow/return or 2 seperated notches ,same goes for the cable1 larger hole or 3 seperated holes

thanks nyck

Title: Re: joist---Drilling & Notching
Post by jasonB on Nov 24^th, 2004, 4:50pm

It is best to place the holes in the middle third of the joist as this will have the least affect on its strength, notching the joists will slightly affect their strength as they will effectively be about 158mm not 175mm

Usually run both copper pipes in the same notch. If you have traditional floor boards put the notch along the center of a board to allow for refixing either side. If running hot & cold feed you may want to use separate notches as the hot pipe will warm the cold water in the adjacent pipe.

Jason

Title: Re: joist---Drilling & Notching
Post by JerryD on Nov 24^th, 2004, 5:16pm

and it's best to notch/drill near the ends of the joists, preferably within about 450mm from one end where it sits in the wall. This has least effect on the joist strength.