Under slab services

[Gibdog]

Hello BuildHubbers,

 

First post for me after months of learning all I can from others on here  We're an MBC passive house build in Stratford on Avon.

 

We need to send the service layout for under the slab connections- can anyone help/comment on the below? Or can anyone share their layouts to give me some ideas?!

 

1. Do all external lights/blinds/Security systems have to be wired directly from inside to out i.e. go through the airtight layer etc, or can you run a duct back under the slab to allow for all external electrics (between TF and timber/brick cladding)? 

 

2. Has anyone had virgin media fitted?  Can this come in under the slab too? At what point do Virgin themselves get involved?

 

3. Water: the mains water will come in under the slab. If we want an external tap, do we need to allow for another under slab pipe back to the exterior?

 

If there's a comprehensive thread on this subject, feel free to send me that way -  feel like I've looked but can't find full answers. Many thanks.

[twice round the block]

Under "foundation" sub section

conduits and services

[Gus Potter]

1 hour ago, Gibdog said:

We need to send the service layout for under the slab connections- can anyone help/comment on the below?

No because you have not provided any drawings!

 

Fesse up and share your drawings. Folk will then chip in and in return we may also learn a bit from you.

 

Them's the rule of the game!

 

[saveasteading]

1 hour ago, Gibdog said:

another under slab pipe back to the exterior?

No. It can spur off before it goes under the house. Take the chance to put stopcocks in all directions.

[deancatherine09]

So here's what we did;

 

1) We specified a separate return duct so all the outside lights and plug sockets go out of the building under the slab, then get routed behind the exterior cladding in the service cavity.

2) We have a specific duct in for the data and CCTV camera wires

3) We have two outside taps, one is teed off before the water pipe enters the house but the other one we ended up drilling through the house from the kitchen as it made sense given the location. We did all the airtightness taping etc and insulated the pipe.

 

You don't want to mix data and power cables in the same duct so map out what you want coming in and out, and go from there. MBC didn't charge us extra for the additional conduits we wanted but we did supply the pipe.

 

[FarmerN]

If you have a plant room or simmilar put at least one spare duct in to future proof for things you have forgotten or not even heard of yet.

[TerryE]

Another happy MBC owner here.  We put some extra 11 cm pipe runs down from the plant cupboard under the slab and out beyond the peripheral path .  We ran various services through these using various flex sleeving covers. These proved great during initial build, but were flawed for future additions -- basically after 2 years of external ground-works and landscaping the external covered pipe end got lost / buried too deep / covered by paving etc.  

 

We had a rule that no trades were allowed to breach the twin-wall, so we did all the through ducts / conduits then once the sparky etc had done using them we foam filled and silicon-sealed them all before the pressure test.  I only wish we'd put some extra through pipes "just in case" as well.  There are no air leaks and tiny U-value hits doing this to it;s a damn site easier drilling one of these out if you need to add extra services later than trying to add a new airtight through duct once the building has been boarded out and plastered / outer skin complete.

 

I ran power and Gb enet to a small shed close the house and added a PoE switch here so that all of the external cameras etc. could be cabled to this shed.

 

Edited Friday at 16:37 by TerryE