PEX repipe- slab leak

[Basod]

Sweated plenty of copper and wish I could repipe with it but unfortunately not happening. This will be my first PEX job and am using Uponor A. I have a cold water slab leak with fittings under the slab- no loop setup- everything was 1/2” copper cold and hot supply’s.

I have my main trunk and most of the replacement branches opened and ready to drill holes- fortunately access from eve space 2 story Cape on a well.

Question 1: PEX does not tolerate UV so in my main supply utility/laundry with a window I should probably stay 3/4” copper and swap to PEX in the overhead joists- thought it might be easier to just cut in the PEX off the well receiver.

Question 2: Master bath and half bath abutt each other and currently share all cold and hot 1/2” copper supply- does it make sense to run 3/4” branches and preserve the above grade copper to limit a full remodel as one of these baths is already remodeled.

Master downstairs that adjoins the half bath has toilet and sink on opposite wall planned on 1/2” to the hot and should I run 3/4 to the sink/toilet then drop to 1/2” or is 1/2” from the end of 3/4” enough.

 

[Basod]

Sweated plenty of copper and wish I could repipe with it but unfortunately not happening. This will be my first PEX job and am using Upunor A. I have a cold water slab leak with fittings under the slab- no loop setup- everything was 1/2” copper cold and hot supply’s.

I have my main trunk and most of the replacement branches opened and ready to drill holes- fortunately access from eve space 2 story Cape on a well.

Question 1: PEX does not tolerate UV so in my main supply utility/laundry with a window I should probably stay 3/4” copper and swap to PEX in the overhead joists- thought it might be easier to just cut in the PEX off the well receiver.

Question 2: Master bath and half bath abutt each other and currently share all cold and hot 1/2” copper supply- does it make sense to run 3/4” branches and preserve the above grade copper to limit a full remodel as one of these baths is already remodeled.

Master downstairs that adjoins the half bath has toilet and sink on opposite wall planned on 1/2” to the hot and should I run 3/4 to the sink/toilet then drop to 1/2” or is 1/2” from the end of 3/4” enough.

 

[Sponsor]

 

[Terry]

You can run two fixtures on 1/2" PEX, so for the hot side you're good on a bathroom. For the cold because you're adding the toilet, that should be 3/4".
You can cover the PEX with pipe insulation if you're protecting it from UV.

 

[Basod]

Thanks for info Terry- and for cleaning up my multiple posts.
Planning all the main trunks in 3/4” with 3/4” drop to master shower, 1/2 bath sink and toilet, then run 1/2” hot to master sink and 3/4 cold to master sink and toilet keeping above grade copper on those.

3/4” tees will hit a 3/4x1/2x1/2 for kitchen sink and washing machine and both those 3/4” will continue to upstairs full bath tied into existing 1/2” copper until a future remodel. The 1/2” feeds come up under the staircase and cold branch to the ice maker.