Ahhh...ducting helll

[SuperJohnG]

I'm close to getting started on Insulated foundation in next 4-6 weeks. 

 

Last night I was awake dreaming of ducts and tossing and turning in bed - I'm a engineer and thinker and like to resolve unknowns logically so I have the solution well in advance of doing everything but I'm not sure how I am going to approach mutliple ducts into my insulated foundation and slab. I've made a short list of what I think will be required:

 

1. Incoming:
   1. Water
   2. Power
   3. BT

 

2. Outgoing
   1. External Lighting
      1. Bollard lights
      2. Front woods
      3. Back woods
      4. Patio lighting
      5. Front gate lights
2. External Power
   1. Borehole Power
   2. Garage (Future plan)
   3. Front gates (Future plan)

 

3. Internal
   1. Island
   2. Power
   3. Water
   4. Waste pipe

 

 

I have a plant room, where all the incomers will go and that's fairly straight forward and easy to sort out. 

 

For the outgoing ducts, I seem to have a million lights I want to control. It's a very big plot, a lot of future planning as I wont be able to do later and don't want to drill holes in the walls or see cables. But I'm struggling on how best to add these cables specifically for external lighting, without using multiple cables and using multiple ducts, which I can imagine will get messy.  Also wanting to control from different locations in the house, E.g. Front woods, from front of house, Back woods from back of house. Or is there a good solution to run power only to a local JB then do a wireless control? (Distance is around max 80m from house either side). 

 

Similarly for external power especially future plans, should I use single ducts and then pulls cables later or a big duct with one or two cables then pull others through later?

 

Island - I was thinking of just putting a duct between main kitchen units and Island, so I can pull power through later for Hob and power (seperate cables!?) then when doing first fix I do a connection somewhere behind kitchen units. Drain can be added easy enough below slab, and water - I suppose just stick a pipe in the slab between island and back of kitchen units I can tie into?

 

The groundworkers have mentioned, covering ducts so they can bull float/ powerfloat over them, then i can dig out later - I don't feel tat confident about this as it might be pain later? especially digging out multiple ducts. 

 

Any input appreciated -lessons learned or pictures especially so. 

 

[PeterW]

Not sure how far they work outdoors but you could use Quinetic switches and receivers for the outside lights ..? I’d run to a couple of strategic locations outside and then run the lights from these. 

[Dan F]

2 hours ago, SuperJohnG said:

1. Incoming:
   1. Water
   2. Power
   3. BT

 

We doubled up on the BT duct, to allow for future cable/fiber internet.  Sometimes these companies don't like sharing ducts.

 

Quote

2. Outgoing
   1. External Lighting

 

Can't you simply take two ducts out; one to garden and one to front gate and then do all external wiring seperatly later?

 

External lights attached to house is a bit different though.  We hadn't planned for this at all, but are now hurriedly trying to work this out before everything gets rendered.  Uplighters wired in as part of lanscaping is one option, but if you want fittings on the facade itself these need pentrations into house or conduits behind renderboard/finnish.

 

Quote

2. I have a plant room, where all the incomers will go and that's fairly straight forward and easy to sort out. 

 

I'd suggest finalizing your plant room layout if at all possible before defining exact duct positions as otherwise duct locations may dictate where things need to go  Don't forget condensate from MVHR, waste water from water softener etc.

 

Quote

For the outgoing ducts, I seem to have a million lights I want to control. It's a very big plot, a lot of future planning as I wont be able to do later and don't want to drill holes in the walls or see cables. But I'm struggling on how best to add these cables specifically for external lighting, without using multiple cables and using multiple ducts, which I can imagine will get messy.  Also wanting to control from different locations in the house, E.g. Front woods, from front of house, Back woods from back of house. Or is there a good solution to run power only to a local JB then do a wireless control? (Distance is around max 80m from house either side). 

 

You'll either need to wire back to a relay/dimmer, or use lights along with a control system (e.g. DALI/DMX or something else).  If you don't want to wire everything back to the house then you'll need to either have relay/dimmers outside the house.. or use a control bus.   Don't you have anywhere in the house, that is outside the thermal envolope where you are left concerned about penetrations, that you could wire everything too?  Or better still some sort of strategic location outside of the house e.g. future location of garage?

 

Quote

Island - I was thinking of just putting a duct between main kitchen units and Island, so I can pull power through later for Hob and power (seperate cables!?) then when doing first fix I do a connection somewhere behind kitchen units. Drain can be added easy enough below slab, and water - I suppose just stick a pipe in the slab between island and back of kitchen units I can tie into?

 

Thats what we did, yes.   Only other reason for ducts between rooms, other that islands, is if you want a in-floor power sockets anywhere.

 

 

 

Edited October 21, 2020 by Dan F

[Declan52]

You leave the ducts covered in the slab by 10-15 mm  so it's easier to break them out. You just tap the concrete at that area and it will sound hollow then you know your there. A few more strikes with a hammer and bolster will remove what's on top. Not a big job to worry about.

[SuperJohnG]

8 hours ago, Dan F said:

Can't you simply take two ducts out; one to garden and one to front gate and then do all external wiring seperatly later?

I can do this, but then I just need to figure out how many cores I need I suppose. Runa multi core cable that would allow me to switch series of lights. Would make better sense to do this, albeit cable might become quite big?

8 hours ago, Dan F said:

I'd suggest finalizing your plant room layout if at all possible before defining exact duct positions as otherwise duct locations may dictate where things need to go  Don't forget condensate from MVHR, waste water from water softener etc

 It's a good shout and that is what I am currently doing, positioning all the equipment at the moment. MVHR condensate is oen thing I hadn't thought of actually! Fortunately, Plant room is attached to utility room hence I have a drain in there I can run to save doing another below the slab. 

 

 

 

8 hours ago, Dan F said:

You'll either need to wire back to a relay/dimmer, or use lights along with a control system (e.g. DALI/DMX or something else).  If you don't want to wire everything back to the house then you'll need to either have relay/dimmers outside the house.. or use a control bus.   Don't you have anywhere in the house, that is outside the thermal envolope where you are left concerned about penetrations, that you could wire everything too?  Or better still some sort of strategic location outside of the house e.g. future location of garage?

I was hoping to avoid smart home stuff, I do have the integral garage which is outside the thermal envelope, I could punch through the wall into. Might make more sense, I've attached full layout for clarity.

 

8 hours ago, Dan F said:

Thats what we did, yes.   Only other reason for ducts between rooms, other that islands, is if you want a in-floor power sockets anywhere.

Thanks. I did start to consider floor sockets for lamps on a 5A circuit but sacked it as I was already contending with this stuff. Resigned to having lamps close to walls.

 

1 hour ago, Declan52 said:

You leave the ducts covered in the slab by 10-15 mm  so it's easier to break them out. You just tap the concrete at that area and it will sound hollow then you know your there. A few more strikes with a hammer and bolster will remove what's on top. Not a big job to worry about.

Makes sense for the ease of power floating, but I was concerned about water pipe, as I am hoping to pull water pipe through duct before pouring, so I know there are not any issues. It'll likely be 25mm MDPE from borehole wellhead. Then obviously with kitchen Island stuff this isn't possible which is a pain.  

 

I've also now remembered the connections for the ASHP, it's a monobloc, so will need power and the fluid connections (2 pipes?!) will these pull through a duct?. MY ASHP will sit right outside plant room. 

 

Thanks for the input so far. 

724-03 Proposals.pdf

[Declan52]

They wont mind if there are only a few ducts to work round. If they do mind then tell them to just get in with it.

[eandg]

On ducting to a kitchen island, a builder has advised just to trunk it through the screed (which will also have UFH pipes) - any thoughts on that approach?

[Russell griffiths]

Why not put a drain in the plant room. 

It will cost pennies, and take an extra couple of hours that’s all, better to have it than to need it. 

 

I have just changed 20m of 32mm water pipe and pulled and pushed it through the duct, two man job but very straightforward, install all ducts with pull cords in them or get one of the tools BT  for pulling cables through, since buying the cable pulling tool I no longer need to leave pull cords in as I can push the fibreglass rod 50m through a duct. 

[Dreadnaught]

5 hours ago, Russell griffiths said:

since buying the cable pulling tool I no longer need to leave pull cords

 

I heard about a trick of sucking a plastic bag attached to a cord through a duct with a vacuum cleaner. Does that work in practice?

[PeterW]

9 minutes ago, Dreadnaught said:

 

I heard about a trick of sucking a plastic bag attached to a cord through a duct with a vacuum cleaner. Does that work in practice?

yes as long as there is a good seal on the vacuum and nothing else in the duct !! Can’t do it once you have a cable or a pipe in there. 
 

Ideally, every time you pull something through such as a cable into a duct, you should also pull another draw cable with it. That way there is always a way to get another cable in.  

[dnb]

1 hour ago, Dreadnaught said:

 

I heard about a trick of sucking a plastic bag attached to a cord through a duct with a vacuum cleaner. Does that work in practice?

It works too well at times. Note to self - remember to tie the other end of the cord to something too big to fit in the duct... extracting the resulting mess from the vacuum cleaner was almost as bad as extracting half a ball of wool from the dog.

[Dan F]

11 hours ago, SuperJohnG said:

I can do this, but then I just need to figure out how many cores I need I suppose. Runa multi core cable that would allow me to switch series of lights. Would make better sense to do this, albeit cable might become quite big?

 

No need to run cables, just put the ducts in with a pull-cord.

 

11 hours ago, SuperJohnG said:

I was hoping to avoid smart home stuff, I do have the integral garage which is outside the thermal envelope, I could punch through the wall into. Might make more sense, I've attached full layout for clarity.

 

We also have integral garage outside of thermal envelope. The garage will have a 3-phase distribution board, PV inverter and potentially future battery/car-charge.  We'll then have a 1-phase consumer unit in the plant room for the house itself.  We have used ducts between garage and plant room to avoid mains cables going through joists.  All electric circuits for garden and front gates will come out of garage, rather than plant room.

 

11 hours ago, SuperJohnG said:

Makes sense for the ease of power floating, but I was concerned about water pipe, as I am hoping to pull water pipe through duct before pouring, so I know there are not any issues. It'll likely be 25mm MDPE from borehole wellhead. Then obviously with kitchen Island stuff this isn't possible which is a pain. 

 

If you ensure there is a shallow bend on 110mm SVP ducting a 25mm MDPE will be a non-issue.  32mm is a much tigher fit with a standard shallow bend though.   I went out to buy some 32mm MDPE just to ensure it went past shallow bend prior to pour.

 

11 hours ago, SuperJohnG said:

I've also now remembered the connections for the ASHP, it's a monobloc, so will need power and the fluid connections (2 pipes?!) will these pull through a duct?. MY ASHP will sit right outside plant room. 

 

We went with pre-insulated pipes for ASHP rather than ducting.  Used REHAU RAUTHERMEX 25mm+25mm/111mm DUO PIPE". @ £22/m.  These need to go in before the preperation for slab, as given the bend radius they need to go quite deep.

[SuperJohnG]

9 hours ago, Russell griffiths said:

Why not put a drain in the plant room

I think I was just avoiding putting multiple drain below the slab, I was trying to tie them all in the house so I had the minimal amount below slab tying together. I was thinking putting small waste pipes down through the slab and tying them in will be a pain to then tie them into the main 110m pipe. 

 

9 hours ago, Russell griffiths said:

I have just changed 20m of 32mm water pipe and pulled and pushed it through the duct, two man job but very straightforward, install all ducts with pull cords in them or get one of the tools BT  for pulling cables through, since buying the cable pulling tool I no longer need to leave pull cords in as I can push the fibreglass rod 50m through a duct.

What size duct did you use for the water pipe?, My mate has a cobra which I think will come in handy! 

 

1 hour ago, Dan F said:

No need to run cables, just put the ducts in with a pull-cord

I was just thinking when I come to pull the cables in. Need to think about duct size just now for whatever size cable it will be. 

 

1 hour ago, Dan F said:

If you ensure there is a shallow bend on 110mm SVP ducting a 25mm MDPE will be a non-issue.  32mm is a much tigher fit with a standard shallow bend though.   I went out to buy some 32mm MDPE just to ensure it went past shallow bend prior to pour.

Do you just use a normal 110mm SVP pipe as the duct for this? or use a specific duct?. I should be 25mm MDPE, don't really see the need for 32mm I wouldn't think. 

 

1 hour ago, Dan F said:

We went with pre-insulated pipes for ASHP rather than ducting.  Used REHAU RAUTHERMEX 25mm+25mm/111mm DUO PIPE". @ £22/m.  These need to go in before the preperation for slab, as given the bend radius they need to go quite deep.

Very helpful thanks - should look into part a little closer. Is this what most people do?

 

thanks all - a lot of good input here. 

[Dan F]

22 minutes ago, SuperJohnG said:

I think I was just avoiding putting multiple drain below the slab, I was trying to tie them all in the house so I had the minimal amount below slab tying together. I was thinking putting small waste pipes down through the slab and tying them in will be a pain to then tie them into the main 110m pipe. 

 

We ended up with two 110mm ducts in plant room for condensate/UVC overflow, just because this was easier than trying to pipe the condensate from one side of the plant room to the other.   Ideally you don't have lots of SVP junctions under your slab, but using Y-junctions for drains that aren't toilets or kitchen sinks is acceptable.  The is a NHBC guidance document called "‘Y’ JUNCTIONS IN DRAINS UNDER BUILDINGS" that talks about this.

 

Quote

Do you just use a normal 110mm SVP pipe as the duct for this? or use a specific duct?. I should be 25mm MDPE, don't really see the need for 32mm I wouldn't think. 

 

110mm SVP pipe supplied and installed by MBC.   If you need 32mm depends how many concurrent high-pressure showers you want to plan for ?.  Costs a lot less to upgrade to 32mm now then do it later which might be impossible, is my POV though.

 

Quote

Very helpful thanks - should look into part a little closer. Is this what most people do?

 

I don't know if most, but some people do.  We felt it was the best approach for us. Depends how far away ASHP is, if you want it highly insulated, if you are happy to cement it in, and if you can go down under harcdcore to acommodate the bend radius or not.  Clearly if you UVC is on an external wall, then this might make less sense and/or be less practical.  The bend radius is about 0.5m+ from memory. Order pipe from https://www.loco2heat.co.uk/.  Photo here.  Note the long run is to a garden room, the short run on the left is for the ASHP.

 

 

 

Edited October 21, 2020 by Dan F

[SuperJohnG]

28 minutes ago, Dan F said:

110mm SVP pipe supplied and installed by MBC.   If you need 32mm depends how many concurrent high-pressure showers you want to plan for ?.  Costs a lot less to upgrade to 32mm now then do it later which might be impossible, is my POV

So just normal  drainage pipe.  I was expecting it would done with an actual duct. Pictures are very helpful  Dan thanks. Part that may be worrying me about drainage is the shallow invert levels I will have,  but I think I changing the sewage treatment plant to a pumped type resolves all that. Then I cam just set it deep and also buy an extension for the head. 

[Russell griffiths]

I ran 32mm mdpe water pipe in 80mm duct, it allowed for insulation around the pipe at the point it comes up through floor, you will pull 25mm in with your eyes closed. 

 

110mm underslab, don’t run small 40-50mm under there. 

[SuperJohnG]

13 hours ago, Russell griffiths said:

I ran 32mm mdpe water pipe in 80mm duct, it allowed for insulation around the pipe at the point it comes up through floor, you will pull 25mm in with your eyes closed. 

 

110mm underslab, don’t run small 40-50mm under there. 

Makes better sense. Did you guys use a someone with a total station to get those drains bang on? or just  measure them out. 

[Dan F]

16 minutes ago, SuperJohnG said:

Makes better sense. Did you guys use a someone with a total station to get those drains bang on? or just  measure them out. 

In our case:

- We had a surveroy set out foundation position.

- MBC then measured drainage position from foundation edge based on drainage drawing provided by designer.  Same with all ther other duct penetrations.

[SuperJohnG]

6 minutes ago, Dan F said:

In our case:

- We had a surveroy set out foundation position.

- MBC then measured drainage position from foundation edge based on drainage drawing provided by designer.  Same with all ther other duct penetrations.

Thanks Dan (you've been a great help here)

 

Did the surveyor just peg out corners, I was thinking that might do then add profile boards or similar, just thought it might be difficult from the low position where there was no hardcore, as when you build might be a pain to keep the position of the EPS without getting surveyor back. I am maybe overthinking it...I am used to engineering tolerances. 

[LA3222]

26 minutes ago, SuperJohnG said:

Thanks Dan (you've been a great help here)

 

Did the surveyor just peg out corners, I was thinking that might do then add profile boards or similar, just thought it might be difficult from the low position where there was no hardcore, as when you build might be a pain to keep the position of the EPS without getting surveyor back. I am maybe overthinking it...I am used to engineering tolerances. 

If you can, get your reference points outside the area you are building up. You need a datum somewhere that you can take your levels from, I hammered a nail into my fence post that serves this purpose as it was easily accessible but safely out of the way.

 

Setting out is where I had difficulties. I had to excavate down which put me in a bowl for all intents and purposes and I couldn't set up profiles outside of this area as they would have been 1.5m above the ground - impractical. This meant i had to keep resetting out from scratch and then measuring as I went for things like drains - luckily its all worked out so far as I can tell.

 

If your surveyor pegs out the footprint set up some profile boards out from them, say 3m or so should get you out of the 'working area'. Profiles about half metre wide then put a nail in on them and run string lines from them that line up with the setting out the surveyor did. You will have to tweet the nail positions slightly as you go in order to get the lines bang on. Once those nails are all in position it doesn't matter what happens with the work the surveyor did as you build the ground up. You can chuck some lines up between those nails and you've got your house marked out again.

 

Ref drainage, like others I marked the house up and measured the 'x' and 'y' position of the drains from the outer walls.

 

Think you can make out my half assed profiles in the pic?

 

The shape of my house made the no. of profiles required a PITA!

Edited October 22, 2020 by LA3222

[LA3222]

One other thing bud, give some thought as to how you set your profiles up - I'm trying to think back now but I recall i had issues at one point.

 

I had a concrete toe beam cast in my EPS which didnt help with setting out. The insulated upstand which the soleplate sits on was quite a bit higher than the outer bit for mine and it was these diagonals I had to use to plumb the EPS. These dimensions are different to when you set the house out though as you do that use the outer corners so in my case the outer corners of the blockwork.

 

I'm confusing myself here now with what I'm trying to get at?‍♂️ .....so I had to set the house out with outer corners of blockwork and then plumb it up with outer corners of soleplate dimensions. Both of which you'll need on your profiles potentially.

[Dan F]

1 hour ago, SuperJohnG said:

Thanks Dan (you've been a great help here)

 

Did the surveyor just peg out corners, I was thinking that might do then add profile boards or similar, just thought it might be difficult from the low position where there was no hardcore, as when you build might be a pain to keep the position of the EPS without getting surveyor back. I am maybe overthinking it...I am used to engineering tolerances. 

 

They pegged out all the interecting lines that formed the corners (1-2 meters from actual house position) and also marked up levels on fence posts. 

Then:

- Groundworker dug formation using these.

- MBC then transferred this to there own small wooden frame type thing to fo mark the position of EPS corners once they'd compacted the hardcore.

Edited October 22, 2020 by Dan F

[SuperJohnG]

34 minutes ago, LA3222 said:

If you can, get your reference points outside the area you are building up. You need a datum somewhere that you can take your levels from, I hammered a nail into my fence post that serves this purpose as it was easily accessible but safely out of the way.

 

Setting out is where I had difficulties. I had to excavate down which put me in a bowl for all intents and purposes and I couldn't set up profiles outside of this area as they would have been 1.5m above the ground - impractical. This meant i had to keep resetting out from scratch and then measuring as I went for things like drains - luckily its all worked out so far as I can tell.

 

If your surveyor pegs out the footprint set up some profile boards out from them, say 3m or so should get you out of the 'working area'. Profiles about half metre wide then put a nail in on them and run string lines from them that line up with the setting out the surveyor did. You will have to tweet the nail positions slightly as you go in order to get the lines bang on. Once those nails are all in position it doesn't matter what happens with the work the surveyor did as you build the ground up. You can chuck some lines up between those nails and you've got your house marked out again.

 

Ref drainage, like others I marked the house up and measured the 'x' and 'y' position of the drains from the outer walls.

 

Think you can make out my half assed profiles in the pic?

 

The shape of my house made the no. of profiles required a PITA!

This is great Jamie thanks. I fortunately have 4 stations already marked out on site with Hilti nails on fencepost from when the topo was done, Just the pisser is they are all +70m from the house footprint as that was the closest solid permanent structures on site as it was a field. I had used them to set out two closer new stations then marked out the house corners using arcs and a 50m surveyors tape, just so I could peg out corners and get a feel for where I wanted to place the house, they are accurate to a few 100mm, but obviously I want to mark perfect from them when doing the foundations. I'm similar that I need to dig down 600mm as I want my house 'in' the ground some what and that's where I may just have to do what you did to some extent.  I have ACAD and all the drawings so getting X and Y positions is fine for everything. 

 

Profile boards now make perfect sense and should work, fortunately no blockwork just render board so might be a little simpler! 

 

BTW - The amount of soil you pulled out the ground  - that's unreal almost! 

30 minutes ago, LA3222 said:

I'm confusing myself here now with what I'm trying to get at?‍♂️ .....so I had to set the house out with outer corners of blockwork and then plumb it up with outer corners of soleplate dimensions. Both of which you'll need on your profiles potentially.

I'm also definitely confused here now ?. When you say plumb, I think 'Vertically plumb. Do you mean square? or am I just totally confused? E.g. when you measure diagonals on a square to make sure it is square and not a rhombus?

 

  

 

[SuperJohnG]

11 minutes ago, Dan F said:

 

They pegged out all the interecting lines that formed the corners (1-2 meters from actual house position) and also marked up levels on fence posts. 

Then:

- Groundworker dug formation using these.

- MBC then transferred this to there own small wooden frame type thing to fo mark the position of EPS corners once they'd compacted the hardcore.

Jammin thanks. Same as @LA3222 profile boards seem to be a good way forward.

 

[Dan F]

@SuperJohnG Once you've worked out ducts, make sure you have UFH layout worked out and give some thought to in-slab temp sensors (assuming you are having in-slab UFH)