150mm Composite deck screed alternative

[bmj1]

I'm working on a community project. Today with the design team we discussed making use of a 150mm composite deck which sits between the steels, and then making use of dry screed (cement) boards on top for ufh pipes to sit in.

 

The reason for suggesting screed board was to minimise build-up.

 

Also important is ensuring no noise transfer between floors (hence 150mm deck).

 

I can't help but think that there must be an approach here where the composite deck could be used as the screed ? Or alternatively we do a 100mm composite deck with 50mm cemfloor/liquid screed on top...

 

Any thoughts on this ? I figure there must be some buildhub wisdom on this...

[Nickfromwales]

This is lacking a lot of info. 
 

150mm composite what?

 

Purpose of building and anticipated w/m2 heating needed, and what’s heating it? 
 

Floor covering? 
 

Lots more detail required or answers will be based on assumptions   

[Conor]

I looked at this. Yes, you save the equivalent of a couple courses of bricks. So what? The cost came out the same, was no faster, was a niche skill that needed additional design and prep. 

 

You'll want a suspended ceiling for minimising sound transfer anyway.

[bmj1]

- composite concrete

- it's a community building/place or worship

- heated by UFH, I imagine using electricity (not gas)

- floor covering likely natural stone tiles

 

Any other questions?

Edited 10 hours ago by bmj1

[Nickfromwales]

4 minutes ago, bmj1 said:

- composite concrete

- it's a community building/place or worship

- heated by UFH, I imagine using electricity (not gas)

- floor covering likely natural stone tiles

 

Any other questions?

Lots.

 

So the most efficient way to heat this would (on the info I have so far) be to have the screed act like a radiator. Minimal mass, achieve heat quickly, turn off as soon as the premises is to be vacated. 
 

Heating up 150mm (plus another 30mm or more of adhesive and stone) of solid mass will take a long time, but will hold heat longer, just need to understand downward / outward heat losses better to say if this is a good idea or not.

 

Absolutely a no brainer to run this off a heat pump, if this is anything like a long term situation.

 

Convenience comes at cost, so the mention of using direct, on-demand grid electricity to do space heating is one where I also assume someone is happy to foot the energy bills per annum?

 

At that stage I’d probably advise the use of in screed electric heater wires, as this is close to 100% efficient, less losses. 

[bmj1]

Hi Nick,

 

Comments as follows:

• I expect the space to be used frequently throughout the week, including a daytime nursery on premises
• So we'll likely want to keep it at temperature from say 6am to 11pm

Does this change anything ? We're building it for ourselves, so we do care that it is cost effective to operate (subject to the capital investment required, but essentially we have an owner mindset on this one)

[bmj1]

I'm particularly surprised by your suggestion for "screed electric heater wires" - my understanding was that wet pipes are much more cost effective to run.

[Nickfromwales]

1 hour ago, bmj1 said:

I'm particularly surprised by your suggestion for "screed electric heater wires" - my understanding was that wet pipes are much more cost effective to run.

Nope. Direct electric is near 100% efficient. 
 

I did I’ve an external heat generator, then wet manifolds, plus ongoing maintenance, losses, and the I detect nature of heat delivery, you’re going to be worse off unless the cost per kwh is managed; so gas or heat pump. 

[saveasteading]

4 hours ago, bmj1 said:

a community project

I've done a few of these, design and construction, including a church, with the starting point being 'someone says you will be able to half the price we've had from tenders'.ie it's not a cathedral and so funds are tight.

 It is complex, based on the use, or variable uses, of the facility, and also the size. Ventilation can be a huge issue as is means of escape , if the numbers are large.

Even which inclination of church and their procedures can make  a difference to performance and choices.

 

But to start with I don't know what you mean by a Composite deck screed.

 

4 hours ago, bmj1 said:

Today with the design team

Does that mean your own steering group, or are there professionals advising? 

[bmj1]

1 hour ago, Nickfromwales said:

Nope. Direct electric is near 100% efficient. 
 

I did I’ve an external heat generator, then wet manifolds, plus ongoing maintenance, losses, and the I detect nature of heat delivery, you’re going to be worse off unless the cost per kwh is managed; so gas or heat pump. 

 

Interesting... so if using electricity - then might as well go for electric UFH - interesting and will put it to the team

[bmj1]

6 minutes ago, saveasteading said:

I've done a few of these, design and construction, including a church, with the starting point being 'someone says you will be able to half the price we've had from tenders'.ie it's not a cathedral and so funds are tight.

 It is complex, based on the use, or variable uses, of the facility, and also the size. Ventilation can be a huge issue as is means of escape , if the numbers are large.

Even which inclination of church and their procedures can make  a difference to performance and choices.

 

But to start with I don't know what you mean by a Composite deck screed.

 

Does that mean your own steering group, or are there professionals advising? 

 

So the knotty areas so far have been:

a) Ventilation requirements: some serious kit and duct sizes involved

b) Fire Strategy: means of escape/staircases

c) Structural design: achieving a very large column-free main prayer space, without a crazy steel bill

I was referring to the professional team (architect, SE, MEP, PM, Interior Designer).

Despite having a full professional team engaged, I certainly plan to keep asking questions here, and keep sharing any findings.

[saveasteading]

5 minutes ago, bmj1 said:

Structural design: achieving a very large column-free main prayer space, without a crazy steel bill

Steel will be the answer. It covers big spaces economically. My rule of thumb is that adding an internal column under a portal frame will reduce that frame by 1/3 in tonnes and cost. What width of building do you intend?

You don't want a column in the middle of your space I'm sure, so make this a fundamental requirement, and accept the cost.

 

9 minutes ago, bmj1 said:

I was referring to the professional team (architect, SE, MEP, PM, Interior Designer).

 

OK, so they should be able to look after you, and will be charging. So anything we say on here might concern them as distrust. 

Have you given them a budget? Would any of them know how to achieve it?