Shop 'Build' for 2014

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Has anyone used solid PlastiSpan HD insulation it is made of expanded polystrene
- approved under slab - R=4/inch as compared to R5/inch for the much more expensive Corning and Dow polystyrene(2' by 8') sheets
It has a 16psi compressive strength or 2,300 per ft sq
3" = R12

http://www.plastifab.com/newsletter/images/plastispanhd.pdf
 
Not trying to be rude but , if your not heating the floor with water or nuheat then there is no meaningfull gain between r values .and the compresional difference is a joke ., dont think that styrofoam is going to hold up your slab. make sure you at least thickin the front edge of the slab, to control cracks and keep the water from getting trapped under the slab then freezing
 
If you are going to heat the garage then use a minimum R12 under your garage slab.
The Type II foam in your link will be fine for under your slab and much cheaper that the closed cell "Dow Corning type"

Floor prep should include the following.
Check with your building inspector or with your Geo-technical engineer if they will allow you to use the fill from your excavation as a back fill material for under your slab. Save money by using the fill, try not to put big rocks under the slab. When the slab settlement occurs it will crack the slab in these areas. (Differential of settlement.) Your fill should be compacted with a 1000 or 500lbs plate tamper in 10-12" lifts. This takes time but well worth the effort. You could get a compaction test done. Your looking for 100 to 110 proctor compaction.


If you can do the following.
Use 3/4 clear crush gravel for the back fill if you can. Easier for compaction, no moisture to wick up towards the slab.
Foam on to top of the compacted fill, then your foam, 6 mil UV poly, your rebar specified by the structural engineer.
You can use rebar chairs or concrete pavers that you break into smaller pieces to lift the rebar up off of the poly.
A good thing to do is also isolate the slab at the perimeter from the outside walls with one inch closed cell foam for a proper thermal break.

Good luck and take care.
 
Hate to see a guy screw up a slab, it is the one thing that is next to imposible to fix. gravel ,gravel, gravel is your freind. as far as the rebar goes make sure its on the right face (closer to the ground is where it should be. ). as far as the thermal brake and expansion joint goes ive been pinning treated 2x4s against the foundation at slab height this acts as a good screet line for the concrete ,wont get eatin by roddents ,,heat, chemicals. can be used for pinning walls or cubbards after, or can be removed to run stuff you forgot to. if your running your own water pipe verse yourself on the proper way to do it . easy and cheap to put in and terminate under the slab with a knockout aand skim coat, this can be converted into a safe later for all the money you saved on your excavation. heck draw an x inside the floor and put a pipe sleeve in the middle of the slab running to it. what no in slab lighting.
 
hey glen Im doing the same here. im just over 2 month in and im passed electrical inspection!! one thing I can recommend to anyone thinking the same.... figure out your budget and add 10 grand haha

IMG_2778.webp
 
Walls are up and stripped - perimeter drains going in to a 1m3 rock drain pit - separate from downspout drains (no storm
P1060478.webp
P1060479.webp
P1060485.webp
 
We are insulating and backfilling the front to get the machine in there today
 
The perimeter drains must be a separate system to the roof downspout drains to prevent roof water backing up to the footing.

All BS since we get so little rain here- water table is very low - no endless monsoon here ...
 
Perimeter drains in with 2" drain rock, covered in felt to rock pit 5 meter from foundation. Poly-Span 3" Insulation inside and outside and all joints sealed and covered in 6 mil poly. Inside insulation cut at 45 degree to top of slab for thermal break.

P1060491.webp
P1060492.webp
P1060494.webp
P1060495.webp
 
Last edited:
Utilities Install
Natural gas line 3/4", water line 3/4", 2 gauge electrical cable, pump up sewer line to septic tank (2" sch 40), telephone 6/24 and Cat 6 went in - all continuous (no connections) sleeved back to the house - with 2x2" and 1X3" cored holes into the basement - 4' deep.
P1060498.webp
P1060500.webp
P1060510.webp
P1060507.webp
P1060497.webp
 
Last edited:
wow, all that in one trench? what finish are you doing on the styrofoam ? double drains in a dry belt to a rock pit sounds over the top. septic tank? I would have thought with the permit hassle you had that you would have been hooked up to city storm and sewer. at least its only one pump. ya the water line is a good cheap sleeve to run for extra insurance for sure. looks like a great man cave save a wall for the big screen....cable.
 
The ground is super boney - 1' to 3'+ boulders - excavation was "as tough as it gets" - Greg and Grayson, who do utility work for Shaw/Telus said to sleeve all of it back to the house - good team .
No storm or city sewer system here- was told that perimeter drains go into a below foundation rock pit 5m from foundation in 2" drain rock (extra cost).
Downspouts go to approved surface drains - 5' away from building.
Middle door is 12' feet - internal height~13.5' (max height I can go)
Today I go for plumbing permit - 2 piece (1 toilet and two sinks back to back between bathroom wall)
 
You must log in or register to reply here.

Share this page

IH8MUD Forum | Toyota, Lexus & Off-Road Community
Community platform by XenForo® © 2010-2026 XenForo Ltd.

© 2000-2026 Tie Rod Media LLC

Back
Top Bottom