watsonpj
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| posted on 5/10/10 at 09:39 PM |
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Central heating Q
I putting in a new central heating system as the old one was very inefficient. The old pipes went in all kinds of directions , one entire loop for
each rad. So i'm putting new pipes in so my question is should I run the pipes just under the floorboards and notch the joists, or is it OK to
run the pipes between the joists and when running across go under the joists. The latter method means I could do it without pulling loads of the floor
up as I'm going under to insulate the floor. The former method means the rad pipes are completely inside the room relative to the insulation but
I need to pull a lot more floor and I need to notch the floor joists.
cheers Pete
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MikeR
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| posted on 5/10/10 at 10:02 PM |
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if you read the guides to notching joists / drilling holes they always drill for electrics (as they have to have a gap between the floor and cable
& notch for pipes.
No idea if you have to notch for pipes but make sure you put the notches in the right place otherwise you risk weakening your floor.
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slingshot2000
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| posted on 5/10/10 at 10:30 PM |
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You should really read and understand the building regs with regard to notching joists as they can prosecute you for doing un-correct work in your own
home, if it is found at a later date (ie;after you have sold it).
The Building Regs have rules laid out for drilling and notching joist. Always drill exactly half way up the height (stops nails from ceiling boards
below, floorboards above; hitting cables).
Multiple holes must be seperated by 3 diameters, minimum.
Holes may only be drilled in the area between 25 and 40% of the total length of the joist (IE; not near the ends or near the middle)!
Do not EVER notch joist that have all-ready been drilled !
(I recently re-wired a terraced house for a family friend. I had drilled 3 holes in every joist from the front of the house to the rear, all spaced
correctly and full of cables (70% max, as the regs insist).
I then caught a brain dead, lazy-b*st*rd of a plumber lifting the same floor boards I had used , busy notching the 5 1/2'' joist with a
jig-saw directly above my holes. His notches were 2inches deep. Sketch it out yourself and imagine how much strength he had removed from EVERY joist
in the house!
Also, if you are crossing any electrical cable with any pipes that may get warm, your pipes should ALAWAYS be ABOVE the cables!(The same plumber ,
mentioned above, also put his main, hot, copper flow and return underneath all my cables!).
I know that once you have installed pipework and replaced flooring, no-one can see what you have done! However, notching joists drastically weakens
them, and this after all, is YOUR home!
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slingshot2000
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| posted on 5/10/10 at 10:36 PM |
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You should really read and understand the building regs with regard to notching joists as they can prosecute you for doing un-correct work in your own
home, if it is found at a later date (ie;after you have sold it).
The Building Regs have rules laid out for drilling and notching joist. Always drill exactly half way up the height (stops nails from ceiling boards
below, floorboards above; hitting cables or pipes).
Multiple holes must be seperated by 3 diameters, minimum.
Holes may only be drilled in the area between 25 and 40% of the total length of the joist (IE; not near the ends or near the middle)!
Do not EVER notch joist that have all-ready been drilled !
(I recently re-wired a terraced house for a family friend. I had drilled 3 holes in every joist from the front of the house to the rear, all spaced
correctly and full of cables (70% max, as the regs insist).
I then caught a brain dead, lazy-b*st*rd of a plumber lifting the same floor boards I had used , busy notching the 5 1/2'' joist with a
jig-saw directly above my holes. His notches were 2inches deep. Sketch it out yourself and imagine how much strength he had removed from EVERY joist
in the house!
Also, if you are crossing any electrical cable with any pipes that may get warm, your pipes should ALAWAYS be ABOVE the cables!(The same plumber ,
mentioned above, also put his main, hot, copper flow and return underneath all my cables!).
I know that once you have installed pipework and replaced flooring, no-one can see what you have done! However, notching joists drastically weakens
them, and this after all, is YOUR home!
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dhutch
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| posted on 6/10/10 at 11:48 AM |
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Yeah, never done it, or read the building regs, but even without i would be look towards passing them in holes in the middle of the joist.
Daniel
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MikeR
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| posted on 6/10/10 at 02:39 PM |
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I found all this out after the lazy electrician had drilled his hole almost directly below the notch 
It worried me so much i googled about what should be done and then panicked and phoned building control. They reassured me in this case i was ok due
to the fact the joist was 175mm thick with a 25mm notch. for the width of room it only needed a 140mm joist so he got away with it...... although i
suspect it was more luck than clever judgement.
Be careful.
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David_17
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| posted on 6/10/10 at 05:39 PM |
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Go underneath the joists and clip your pipes to the underside.
You'll need to notch some of the upstairs ones, depending on where you run your pipes.
Alot will be already notched for the old ones, you may need to make them slightly wider.
A few tips, dont use 15mm for feeding more than 2 rads (or 3 small ones), and put some pipe lagging on under the floor down stairs.
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BenB
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| posted on 6/10/10 at 05:54 PM |
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As said check out the regs for notching and drilling. There are safe zones and prohibited zones. If you look at the forces applied to a beam
you'll quickly understand why....
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