Help with detail drawing

[PatrickBateman]

Hi, I'm new here! Firstly I hope i've posted this in the correct place, please do let me know if i've made an error and flag my in the direction of a better home for this post!

 

I am a pretty experienced builder, having worked on my own projects, mostly renovation of existing structures, hence me being a bit out of my comfort zone here. 

 

Is the below detail / build correct? What can I improve? Any help / comments would be very appreciated. 

 

CheersTimber Frame Retaining Wall.pdf

[PatrickBateman]

Timber Frame Retaining Wall.pdf

[Mr Punter]

A few things:

 

Is this habitable space?  Will it need to meet building regs?

 

The waterproofing does not look very robust.  A proper tanking membrane would be better.

 

The drip tray flashing may act as a tray to hold water which would rot the battens and frame at the bottom.

 

The sole plate should be min 150mm above ground level.

 

Taped joints in the Celotex is not a great VCL and a sheet of polythene may work better or in addition.

 

The 50mm screed would need to be liquid as it is too thin for traditional s & c.

[PatrickBateman]

1 hour ago, Mr Punter said:

A few things:

 

Is this habitable space?  Will it need to meet building regs?

 

The waterproofing does not look very robust.  A proper tanking membrane would be better.

 

The drip tray flashing may act as a tray to hold water which would rot the battens and frame at the bottom.

 

The sole plate should be min 150mm above ground level.

 

Taped joints in the Celotex is not a great VCL and a sheet of polythene may work better or in addition.

 

The 50mm screed would need to be liquid as it is too thin for traditional s & c.

Hi Thanks for your reply - some really helpful feedback.

 

The space is a garden room and as such falls outside regs - that said I want to create a high quality space. The idea for building off the retaining wall is to gain a bit of extra head height under permitted as the retained ground level would form the measuring point for the 2500 permitted height. 

 

I agree a membrane would be a better solution - its a pretty small wall so wouldn't represent a huge outlay and would certainly increase the longevity of the build - would a product like this be suitable? https://www.ukbuildsupplies.com/2000sa-self-adhesive-waterproof-hyload-tanking-membrane-15m-x-1m?gad_source=1&gad_campaignid=22574627952&gbraid=0AAAAADtJMBNpGY3KJJ0Nb6SCW4tisYEFM&gclid=Cj0KCQjw1JjDBhDjARIsABlM2SuY6aoDHlhRaQrsvVqYePl0CXFTw33EL1O3KIJ7424SXRMob0k0yK4aAvEQEALw_wcB

 

Re the drip tray "holding water" - could you please help me understand this feedback? I understand the drip tray would move water away from the structure and as such I'm a little confused as to your input here but keen to learn more!

 

The drawing as shown allows 100 mm above the ground for the sole plate so I can find an extra 50mm there to be safe!

 

Adding a vapor barrier seems sensible! Good advice. 

 

Re the screed - what's the min depth for a traditional S&C mix?

 

Thank you in advance!!

[Mr Punter]

With the drip tray as long as it directs water away from the building it will be OK.  From my first view it looked like it was going between DPC and blockwork but I see it is l shaped.

 

Traditional screed would be 75mm.

[PatrickBateman]

1 hour ago, Mr Punter said:

With the drip tray as long as it directs water away from the building it will be OK.  From my first view it looked like it was going between DPC and blockwork but I see it is l shaped.

 

Traditional screed would be 75mm.

Thank you - That's very helpful for shaping my thinking.

 

I don't suppose you looked at the water proofing membrane I linked - I have never used one of these before so I would appreciate any input you might have. 

 

I've will rework the drawing and post them here later on - I'm new to this forum but so far finding it a very helpful place to be! Cheers.