# Basement renovation



## jcdammeyer (Dec 11, 2022)

Bit of history first.  The house is built into a hill so the front of the house is at ground level but it's really the basement.  Stairs go up to the main level which is pretty well even with the ground level and the upstairs driveway.  The basic foundation at the front is concrete about 8" wide or so.  The framing for the front sits on this. 

When we bought the house in 1997 we took out this old beat up shag carpet that was laying on the concrete and tossed it.  The carpet on the main floor was pulled, the hardwood refinished and that carpet laid on the floor downstairs in what we called the family room.

A few years ago we replaced all the single pane aluminum framed windows (lots of ingots from that) with Pella Wood framed double and triple glazed.  Downstairs in this family room it was roughed in after we pulled some of the wall paneling and there it has sat for the last 8 years or so.

The thin ugly wood paneling was spaced away from the framing to match the original aluminum frames.  I can pull this now and add plastic vapor barrier and drywall.  What I don't know is what to do with that concrete footing which sticks out from the wall.  In fact the lifting the carpet shows lots of spider infestation over the decades and a layer of sand along the footing on top of the concrete floor.






So once I remove the spacers I'm thinking 3/4" foam board to wrap around the footing.  For the floor those floating 2x2 foot panels with a vapor barrier under them too. 

I'm thinking the wall vapor barrier goes over the foam and is connected to the floor vapor barrier. 

So what order to do this?
1. Rip out all the wall panels to get access to the footing and lay down plastic and the floor panels.
1a. Or use the foam backed floor panels and forget about the plastic on the floor.
2. Put the foam panels over the footing.
3. Put on the wall vapor barrier and tape it to the floor plastic barrier that has been brought up.

Or is it better to lay the plastic on the floor and the foam on the footings and first tape the vapor barrier from wall to floor.  Then put down the floor panels and cover the foam with plywood.  Finally add the drywall?


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## LenVW (Dec 11, 2022)

A while back I documented a Norwegian forming line for a Foundation Membrane product.
It was a sheet of Polyethylene that had Dimples formed in it to hold it off of cement walls. This created a small air gap which increases the insulation R Factor for heat retention.
The idea was to allow for any ground water to drain away in the cavity created by the Dimples.
The ground water would drain directly to the perimeter tile at your footings.

The Membrane worked so well that they also used it on cement basement floors to create an insulation pocket of neutral air.
‘PLATON Membrane’ is sold by building centres all over Canada.


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## TorontoBuilder (Dec 11, 2022)

jcdammeyer said:


> Bit of history first.  The house is built into a hill so the front of the house is at ground level but it's really the basement.  Stairs go up to the main level which is pretty well even with the ground level and the upstairs driveway.  The basic foundation at the front is concrete about 8" wide or so.  The framing for the front sits on this.
> 
> When we bought the house in 1997 we took out this old beat up shag carpet that was laying on the concrete and tossed it.  The carpet on the main floor was pulled, the hardwood refinished and that carpet laid on the floor downstairs in what we called the family room.
> 
> ...


John I made my living doing consulting on building science and just such renovations... if you want to ask me anything I'd share my cell phone number with you.


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## TorontoBuilder (Dec 11, 2022)

LenVW said:


> A while back I documented a Norwegian forming line for a Foundation Membrane product.
> It was a sheet of Polyethylene that had Dimples formed in it to hold it off of cement walls. This created a small air gap which increases the insulation R Factor for heat retention.
> The idea was to allow for any ground water to drain away in the cavity created by the Dimples.
> The ground water would drain directly to the perimeter tile at your footings.
> ...


Platon membrane is a great product for what it was designed to do, which is provide a drainage plain on exterior foundation walls.  

It is also okay under floating floor systems IF you need active ventilation system to deal with radon, but mostly an unnecessary expense otherwise.


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## TorontoBuilder (Dec 11, 2022)

jcdammeyer said:


> Bit of history first.  The house is built into a hill so the front of the house is at ground level but it's really the basement.  Stairs go up to the main level which is pretty well even with the ground level and the upstairs driveway.  The basic foundation at the front is concrete about 8" wide or so.  The framing for the front sits on this.
> 
> When we bought the house in 1997 we took out this old beat up shag carpet that was laying on the concrete and tossed it.  The carpet on the main floor was pulled, the hardwood refinished and that carpet laid on the floor downstairs in what we called the family room.
> 
> ...


There is no functional difference between 2x2 osb panels with foam backing, and 4x8 t&g osb over foam sheets... but the 4x8 is faster to lay and cheaper.

Frankly the 2x2 panels are marketing bs and the space of their grooves is too small to affect any air movement or sub-floor ventilation.

IIRC you're in central saanich right? Any granite protrusions in your foundation, or moisture issues?


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## jcdammeyer (Dec 11, 2022)

No moisture issues.  I redid the perimeter drain at the front of the house.  The pros redid it around the rest since the back side was a full 8' deep.  I no longer have rivers flowing through my shop.  The lower level has now been dry for a few years so now I feel confident about installing flooring.

In my office on the other end of the house tiles were glued directly to the floor.  The concrete footing was just painted.  The other day I noticed there's a bit of a crack in the plaster they had put over the concrete foundation.  This section is behind the door which is almost always open so not a lot of air flow.  Condensation and dust over 25 years.  Needless to say I will want to do the same thing on this side.


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## TorontoBuilder (Dec 11, 2022)

If you dont have moisture issues I'd just float a floor with full size 4x8 sheets with staggered joints. I'd extend the wall and footing assembly into one with pressure treated 2x2s so you have 1 1/2" around the perimeter to trap a floating floor edge.  But i'm not sure if you'd have room behind the door. It depends on what's under that plaster.


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## TorontoBuilder (Dec 11, 2022)

ps, you only need to extend the wall vapour barrier over the footing and out over the floor 10" or so. When you cover floor with 1/2" extruded polystyrene (a vapour barrier in itself) the overlap of 10 inches is sufficient to seal between the two products to prevent vapour movement


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## jcdammeyer (Dec 11, 2022)

TorontoBuilder said:


> If you dont have moisture issues I'd just float a floor with full size 4x8 sheets with staggered joints. I'd extend the wall and footing assembly into one with pressure treated 2x2s so you have 1 1/2" around the perimeter to trap a floating floor edge.  But i'm not sure if you'd have room behind the door. It depends on what's under that plaster.


The windows are even with where the drywall would be if fastened onto the 2x4 studs.   My office is already finished other than the now cracking plaster in one place on the foundation.  Don't really want to tear all that out to build out the wall and have to also build out the window frames.

It doesn't get really cold here so I suspect even just the same kind of thin foam that wall studs are placed on would be more than enough insulation with then a 3/4" covering.

Yes it leaves this border all around the perimeter walls but at the front entrance there is no footing.  It's flush with the concrete floor (which has parquet food glued down.  The side light windows had some sort of trim there.  Long gone.  Our plan is to replace the door and have opening sidelights.






Anyway, I can live with an insulated footing that protrudes outwards a tiny bit more than the existing concrete.


TorontoBuilder said:


> If you dont have moisture issues I'd just float a floor with full size 4x8 sheets with staggered joints. I'd extend the wall and footing assembly into one with pressure treated 2x2s so you have 1 1/2" around the perimeter to trap a floating floor edge.  But i'm not sure if you'd have room behind the door. It depends on what's under that plaster.


Just the concrete under the plaster.  It's maybe 1/2" thick.


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## TorontoBuilder (Dec 11, 2022)

jcdammeyer said:


> The windows are even with where the drywall would be if fastened onto the 2x4 studs.   My office is already finished other than the now cracking plaster in one place on the foundation.  Don't really want to tear all that out to build out the wall and have to also build out the window frames.
> 
> It doesn't get really cold here so I suspect even just the same kind of thin foam that wall studs are placed on would be more than enough insulation with then a 3/4" covering.
> 
> ...


I was just trying to see how to maintain continuity of the vapour barrier, but the correct paint on the footings can do that... 

I really just wanted to ensure that you knew that extruded foam is a vapour barrier so no need to first put down plastic sheet type barrier. Just seal the cracks between the foam sheets with VB tape.


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## jcdammeyer (Dec 11, 2022)

TorontoBuilder said:


> I was just trying to see how to maintain continuity of the vapour barrier, but the correct paint on the footings can do that...
> 
> I really just wanted to ensure that you knew that extruded foam is a vapour barrier so no need to first put down plastic sheet type barrier. Just seal the cracks between the foam sheets with VB tape.


Thanks.  That's helpful.   Looking at the North wall it appears to also have the footing for at least part of it.  The back half of the basement has concrete all the way up.  
The reason I can't tell if there is a footing is because there are built in bookshelves from the corner to the middle of the room where the downstairs fireplace sits.  We're short of book shelves as it is.  Maybe that's the best solution.  Build out the wall in such a way that book shelves frame the large window and hide the concrete footing.

In my office with that door hinged right at the edge of the footing I'd have to do far more work and the type of ornamental plaster on the walls would be hard to duplicate.

House was built in 1967.


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## jcdammeyer (Dec 11, 2022)

None of this is going to happen really quickly.  Just I saw all the crap on the concrete footing when I was cleaning and that started the thought process.

When we do the reno all depends on how long Anja stays with us.  The breed averages 12.8 years and our other one took her last breath at 14 years, 2 months at which point she was the oldest in North America.  

Anja is 12 now;  suffered cognitive damage from a stroke in the ER when her spleen ruptured from a malignant tumor.  She was given 1 to 3 months and has now survived 4.5 years without a spleen.    

However she can't handle banging from construction and as she gets older she's definitely getting more batty and klingy.  Hard to work in the shop which due to metal chips is off limits for her.  The Trazodone is helping with her being anxious but even so we cannot travel or leave her for more than a few hours.  

This photo of her is when she was  a bit younger.  Still looks exactly the same except for some grey around the muzzle.







__





						Ameri-Can Stabyhoun Association
					






					www.stabyhouns.org


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## TorontoBuilder (Dec 11, 2022)

jcdammeyer said:


> None of this is going to happen really quickly.  Just I saw all the crap on the concrete footing when I was cleaning and that started the thought process.
> 
> When we do the reno all depends on how long Anja stays with us.  The breed averages 12.8 years and our other one took her last breath at 14 years, 2 months at which point she was the oldest in North America.
> 
> ...


what a beautiful dog


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## jcdammeyer (Dec 11, 2022)

Here's a family picture of Mom and the kids at 1 year old.  We took her back to The Netherlands for that.  Mom (Senna) is 4th over from the right.


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## TorontoBuilder (Dec 11, 2022)

jcdammeyer said:


> Here's a family picture of Mom and the kids at 1 year old.  We took her back to The Netherlands for that.  Mom (Senna) is 4th over from the right.
> View attachment 28833


wow what a family


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## Dabbler (Dec 12, 2022)

An alternative *if you have the head room* is to use 8' wide roll form Delta FL - a dimple product for elevating floors 1/2" above concrete, and putting it on 1" structural foam.  You can then use 1/2" tongue and groove ply.  

What this buys you:  

1) you get great insulation and great ventilation - the concrete always weeps water vapour, and this helps to ventilate it.  if the vapour is not vented, it can deteriorate the concrete over a long period of dampness.

2) it is about the fastest and least labour intensive way to do a floor.

3) vapour barrier is not needed as long as you take minimal care in your foam seams. (or you use expanding foam for the odd gap)

We did half of our basement this way, and we noticeably saved in heating costs.  Oh and yes I was a building contractor for 20 years....


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## TorontoBuilder (Dec 12, 2022)

Dabbler said:


> An alternative *if you have the head room* is to use 8' wide roll form Delta FL - a dimple product for elevating floors 1/2" above concrete, and putting it on 1" structural foam.  You can then use 1/2" tongue and groove ply.
> 
> What this buys you:
> 
> ...


not really true and studies of many basements have proven this... because the sub concrete capillary break there is not enough moisture to cause any issues, and the moisture present will find a bypass around any vapour barrier placed over the floor itself. An air gap is only beneficial if you have active sub floor ventilation system with a fan otherwise there is very little air movement and moisture transport.  If a product does not provide a clear proven benefit why waste money on it?

Also, the delta T across the floor is such that there is no real world benefit to providing more than 1/2 extruded polystyrene. A floating floor with OSB or plywood directly over 1/2" insulation board feels warm to bare feet. This is all you need and take minimal height away.

The only time I'd recommend an air gap membrane is if you had radon to such an extent that you needed to install active subfloor ventilation and you had a reason not to demo the concrete to place such a system under the slab itself. Or perhaps in the very very rare situation of having an active spring below your foundation... and I've only seen that in a condo in york region

I was formerly the Director of Programs and Technical Services for the company that ran Building Canada in Ontario for the federal govt, as well as R2000, Energuide for New Houses and Energy Star for New Homes, among the many other consulting and design hats I wore. My knowledge is informed by years of research data collection and validation on 1000s of homes, since we started speaking about qualifications on this particular issue


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## Dabbler (Dec 12, 2022)

I accept your statements, however, my experience varies.  

I have fixed dozens of basement floors that were incorrectly renovated.  

A typical problem is 8mil vapour barrier, plywood, and flooring material.  The concrete spalls so badly that you have to do a restoration to it.  The concrete is chalky and lacks strength.  The only correct mitigation is to remove all the weak concrete and pour topping compound and redo the floor properly.

Not one of my renovations has needed any mitigation, at very small extra cost.


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## TorontoBuilder (Dec 12, 2022)

Dabbler said:


> I accept your statements, however, my experience varies.
> 
> I have fixed dozens of basement floors that were incorrectly renovated.
> 
> ...


Nor have mine. Including the legal basement apartment I built in my old home 25 years ago... we had data logging in that house for 3 years until I sold it.

I now remember why I had decided to stop trying to help people with housing related issues, everyone has anecdotal experience that trumps years of industry leading research.

Good luck on the basement BC John I'm unwatching this thread now to avoid any arguments


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## Dabbler (Dec 12, 2022)

In theory, there is no difference between practice and theory. In practice, there is.


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## jcdammeyer (Dec 12, 2022)

Gosh some buttons pressed here.  I guess I won't mention the conflict I had with the contractor doing the perimeter drain replacement.  His opinion of that plastic bubbled material to help water slide down into the drain was that it was crap.  I suspect he just didn't want to pay for it and remain competitive with other bids.  Or maybe it is crap.  In either case it wasn't done on ours.  What they did do is glue down that blue covered black sticky rubber for 2' above the footing and over the footing.  

Let's not go there...

John


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## Darren (Dec 12, 2022)

I do a few basement exterior waterproofing jobs per summer as a side gig. Always Blueskin/dimple board membrane/fabric wrapped weeping tile, lots of 3/4" clear stone wrapped up in fabric then backfill. Never had to go back and redo. The dimple board membrane adds to the cost, but protects the blueskin from mechanical damage during backfill and adds another drainage layer. Its maybe 6-700 extra for the average house.


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