Preparing to Screed - What to consider....

[Mulberry View]

I have a Beam & Block floor and am hoping to screed soon. I have 230mm of insulation going in, it's all here on site. The Beam & Block is grouted and fully dry. The grout has "cracked" in places, but just superficially. There are gaps in places at the perimeter to the subfloor. Should these be sealed?

 

I have 4 soil pipes and a blue 110mm water pipe duct coming up through the floor blocks. Do these need to be specially sealed in any way at Beam & Block level? The soil pipes are plain ended and currently plenty long enough, should I solvent weld socket couplers in the insulation level to remove the joint that faces the wrong way or just live with the plain pipe ends and worry about connections later above the floor level?

 

Do I need to consider air-tightness in the way to DPM is installed and terminated onto the Nudura walls? PIR upstand yes or no?

 

The screed is likely to be Cemfloor at a thickness of 50-55mm, containing UFH (yet to be installed of course).

 

Any tips or words of advice to limit my inevitable procrastination would be massively appreciated.

[Russell griffiths]

Get some neoprene insulation material 100mm wide, wrap this around the soil pipes at screed level. 
2 wraps around will leave you with a void around the pipe so when the screed is in and dry you will either have a bit of wiggle room on the pipe, or you have the ability to pull the neoprene out which leaves a void that a pipe coupling will fit into. 
as for sealing them you will be putting your dpm on top of the beam n block so you seal the pipes to that. 

[JohnMo]

I made insulation corners a bit bigger than the tape lines to enable lots to wriggle room. Once screed had cured, broke out the insulation. Did what I needed when bathroom etc was being done, then back filled with cement mix.