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MVHR ducting routes...


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Hi All,

We are a few months away from starting the hard graft on site, but I am already trying to "guess" the possible ducting routes within the building.

My worry is that our timber frame structure has got a lot of steals and glulams in floor zones. One plan was to position the unit in the loft space. Alternatively, fit it inside the utility.

 

With steels cutting across both floors north to south and west to east, I can't see how, or where else I would have all pipes running between floors and rooms without adding quite unsightly boxings in numerous locations.

 

See the plans for more clarity.

 

Any hints please?

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What size is your house? If you're in the 300m² ballpark, you might want to consider two units, one for each side of the house to avoid crossing steels. That's what we had to do as we couldn't cross the steel mezzanine that splits the house I'm half.

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Hi,

We are merely 180sq m (90 GF, 70 1st, 20 2nd floor). Sounds that I will end up with a lot of boxed out walls in the process, as the steels span the full height of the floor zones, so not like it is going to be possible to go flat ducting anywhere.

 

 

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7 minutes ago, BartW said:

Hi,

We are merely 180sq m (90 GF, 70 1st, 20 2nd floor). Sounds that I will end up with a lot of boxed out walls in the process, as the steels span the full height of the floor zones, so not like it is going to be possible to go flat ducting anywhere.

 

 

This is an example of folk not involving an M&E early on in the build process. All of my projects have the steels Pre-drilled for MVHR and FW/WW etc and permissions in place for drilling through glulams. 

Can you ( have you thought to ) petition the SE to ask if you could have the steels penetrations done retrospectively? 
In other projects I have reduced the 92mm ducts to 25mm x 225mm rectangular ducts to get up inside the service cavities of an MBC TF and that negated a lot of unsightly boxing in. Don’t know if that can help you out

with some of the runs, or maybe going from round to ‘oval’ ducts and mechanical 90o bends etc. 

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12 minutes ago, Nickfromwales said:

This is an example of folk not involving an M&E early on in the build process.

 

This is an example of not reading the first post ;)

 

12 minutes ago, Nickfromwales said:

Can you ( have you thought to ) petition the SE to ask if you could have the steels penetrations done retrospectively? 

 

I have not thought this would be even possible. My assumption was that drill holes in steel were only acceptable for small holes for likes of 40mm waste pipes, or cables. Nothing as big (and numerous), as MVHR ducts. But I will certainly enquire!

 

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24 minutes ago, BartW said:

 

This is an example of not reading the first post ;)

 

 

I have not thought this would be even possible. My assumption was that drill holes in steel were only acceptable for small holes for likes of 40mm waste pipes, or cables. Nothing as big (and numerous), as MVHR ducts. But I will certainly enquire!

 

Ah, yes it is. You got me lol.

Also, an example of answering your own question then?

21 hours ago, BartW said:

Any hints please?

Yes. Get your M&E coordinator to design everything to fit into the fabric of the build, have the steels etc pre drilled...... :S 

On my current clients MBC PH build, the in-house designers and I, plus the SE, did all this in advance. 300mm posi joists met 252mm steels, so no gap for 92mm ducts to go under ( above the ground floor ceilings ). I asked for the grade of the steel to be beefed up, and the profile reduced to 202mm. Job done. We now have 98mm under the steels which a) gives free run throughout the ground floor, and b) negated having any holes made ( bar 1x 117mm FW hole in 1x UB ). 

Plumbing / electrics / mist system / MVHR / and FW+WW all in without a single boxing in.

Hopefully your TF company can work with you to do the same :) 

Edited by Nickfromwales
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43 minutes ago, BartW said:

@Nickfromwales yes I have engaged with English Brothers regarding this, and it sounds that they should be able to help in this regards.

 

Thanks for advice again :)

 

??.Have you asked for pozi joists @ 400mm centres instead of 600mm? Makes a HUGE difference in the bounce in the floors. If it was my house I’d also ask for extra strong-backs on the longest spans. Pennies in timber, priceless in results. 

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40 minutes ago, Nickfromwales said:

Makes a HUGE difference in the bounce in the floors.

It shouldn't, as joists are designed for strength and also to a maximum deflection which memory says is 0.03 x span. 

 

Although the reality will be of spreading a walking load over more adjacent  joists, so yes, you are probably right.

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Yes they are designed for a maximum deflection but Nick is spot on regarding bounce.

Pozi’s behave very differently from solid timber or I beams in that the “broken” web allows top and bottom cord to act like elastic as opposed to deflect and return

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2 hours ago, Nickfromwales said:

??.Have you asked for pozi joists @ 400mm centres instead of 600mm? Makes a HUGE difference in the bounce in the floors. If it was my house I’d also ask for extra strong-backs on the longest spans. Pennies in timber, priceless in results. 

 

I remember specifying deflection at max 8mm, but that was 14 months ago, so I should revisit. I think they are 600c/c but perhaps beefed up enough to assist.

 

I shall check engineering notes when the structure has been approved.

 

 

 

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2 hours ago, BartW said:

 

I remember specifying deflection at max 8mm, but that was 14 months ago, so I should revisit. I think they are 600c/c but perhaps beefed up enough to assist.

 

I shall check engineering notes when the structure has been approved.

 

 

 

Engineering will tell you that the deflection is ‘fine’ which means it’s to the maximum that you will tolerate. That’s not a good standard to strive for in your own dwelling ;) 

4 hours ago, saveasteading said:

so yes, you are probably right.

No probably about it. Been in houses that have been built both ways and the difference is massive, not slight.

Folk should also remember that if they want to use alu spreader plates for UFH they need 400mm centres. 

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2 hours ago, Nickfromwales said:

Folk should also remember that if they want to use alu spreader plates for UFH they need 400mm centres


we are doing overlay eps400 with alu coating on top of the mfc deck as simpler to run pipes. 
 

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There is an alternative, which is to design in ceiling features that can conceal where the pipes go under the steals. We’ve done this in our master bedroom and created a nice effect in that we have a sort of decorative cornice all around our room, but it is much bigger than a regular cornice. Not only does this allow the ducts to run through that perimeter area (and past the steel) but it also offers opportunities for LED lighting in the recess and a concealed curtain rail as well. Create a really nice architectural effect.

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1 hour ago, BartW said:

we are doing overlay eps400 with alu coating on top of the mfc deck as simpler to run pipes. 

You’re decking the floor twice then though?

It doesn’t get much simpler than alu plates, tbh, but if you’re DIY’ing then do what you feel most comfortable with. 
You using that ground and 1st floors? Or just 1st? 

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13 hours ago, hendriQ said:

There is an alternative, which is to design in ceiling features that can conceal where the pipes go under the steals. We’ve done this in our master bedroom and created a nice effect in that we have a sort of decorative cornice all around our room, but it is much bigger than a regular cornice. Not only does this allow the ducts to run through that perimeter area (and past the steel) but it also offers opportunities for LED lighting in the recess and a concealed curtain rail as well. Create a really nice architectural effect.

 

Our ceiling heights are only 2.4m, also the interior is going to be quite (very?) modern looking with floor to ceiling glazing so this would not work here sadly, but good idea otherwise.

 

13 hours ago, Nickfromwales said:

You’re decking the floor twice then though?

It doesn’t get much simpler than alu plates, tbh, but if you’re DIY’ing then do what you feel most comfortable with. 
You using that ground and 1st floors? Or just 1st? 

 

It is a bit more complex than this. I would have gone for spreader plates under the deck, but the Timber Frame supplier has a programme that does not allow time for me interlacing with plates and pipes. Moreover, the heat output of plates below 22mm deck is a lot less than pipes sitting directly under the finished floor layer. So overall, better performance and reaction time.

 

I thought of routing in the MFC deck, but worried it would be quite laborious, and would weaken the deck integrity. EPS adds to the overall sound absorption too.

 

Ground floor will have in-screed pipes, and the overlay is on 1st and 2nd floor.

 

 

 

 

 

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On 07/02/2022 at 15:40, Nickfromwales said:

Yes. Get your M&E coordinator to design everything to fit into the fabric of the build

 

Another approach is to ask the TF supplier to add 3 inches to the height of the ground floor and put in a suspended ceiling. Our TF supplier did this at no cost.

 

This means the ducts can all go under the steels etc.

 

Simon

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42 minutes ago, Bramco said:

 

Another approach is to ask the TF supplier to add 3 inches to the height of the ground floor and put in a suspended ceiling. Our TF supplier did this at no cost.

 

This means the ducts can all go under the steels etc.

 

Simon

Ok if you can gain 3" of height at the ridge, or compress the height of the 1st floor spaces? The 3" has to come from somewhere??

Edited by Nickfromwales
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59 minutes ago, Nickfromwales said:

Ok if you can gain 3" of height at the ridge, or compress the height of the 1st floor spaces? The 3" has to come from somewhere??

 

Just lifted the upper floor and ridge.  But don't tell anyone  ?   ? 

 

Simon

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