New garage build with attached house :)

[wsettle]

I have started building my first home and it will have a 20' wide by 44' long drive through garage. Of course, I'll never have a clean enough garage to actually drive through but since it is on a steep slope, I have to limit my garage width since I'm terracing the hill side. It will have a garage door in both ends which will be different.

I hired a crew to build the retaining wall and a storm shelter using Symon forms and now I need to prep and water/damp proof the concrete walls before I back-fill. I have googled this topic to death and have come up with so many ideas and opinions it is confusing so I am hoping some of you can help guide me in the right direction. The concrete guys I hired do not do water proofing so I'm looking for some ideas.

I believe the general process for water proofing is:
* prepare the walls by sanding/grinding the surface to remove all delaminated plywood, paint, grease and ridges from forms, as well as any other surface defects
* fill all bug holes, snap-tie cavities and low spots from form seems to make the surface smooth
* apply an elastomer coating to seal it (any recommendations on which brand/type?)
* optionally add membrane to protect the waterproof coating
* optionally add foam board for thermal break before back filling
* install french drain, wash rock and geo-fabric before back-filling

Does my water proofing list look reasonable or is there something I'm not considering?

This is my only chance to get this right so I need to take my time and figure out exactly what I need to do before tackling it.

And for everyone's enjoyment, here are the obligatory pics to accompany my build. All concrete walls and storm shelter roof is 8" thick with #5 rebar @12" horizontal and vertical. The storm shelter roof was poured monotonically with the walls so it is one seamless box.

Concept drawing of the house and where the storm shelter is located under it...

Garage view...

 

[wsettle]

Cleaning the surface of the concrete

Here are a couple of pics of my next task which is to clean the surface before applying the waterproof coating. The red circle is where I used a diamond cup wheel to lightly scratch the surface. I was surprised at how many bug holes it exposed. Is all concrete like this?

My plan is to lightly grind the surface to make it clean and smooth and then fill all of the holes with cement.

Is grinding the surface a common approach or is there a better way?

Here are some pics of an area I have ground smooth. The red line indicates where I was working. The last pic is the diamond cup wheel I'm using.

 

[MacTexas]

I am no expert but , why do you have to fill the holes and make them smooth? Won't the water proofing you apply just fill the holes and still be waterproof? Seems like it would save a lot of work and expense.

 

[LB-1911]

By "optionally add membrane to protect the waterproof coating"
are you referring to a Air Gap Membrane**

Additional information @
**http://www.waterproofmag.com/back_issues/200801/dimple_membranes.php

 

[skamp]

You may want to PM LLWillysfan. He is an expert in concrete.

Steve

 

[mooseracing]

In your garage view picture, it looks like your house windows are just above the garage roof. The windows better be wrapped real well or they/and wall will rot from all the splash back you will get. Just an FYI from other house repair experiences.

 

[wsettle]

Won't the water proofing you apply just fill the holes and still be waterproof?

I've never done this but when I read the instructions on how or apply an elastomer coaring (tar like), they read like "surface must be clean, dry and free of surface defects".

Now it is possible there is a spec to the SIZE of the surface defect that I haven't read about yet. Maybe the coating will fill any hole that is smaller than a certain size. I'll keep reading unless someone knows but I suspect it will be product specific.

 

[hockey88fan]

I've never done this but when I read the instructions on how or apply an elastomer coaring (tar like), they read like "surface must be clean, dry and free of surface defects".



Now it is possible there is a spec to the SIZE of the surface defect that I haven't read about yet. Maybe the coating will fill any hole that is smaller than a certain size. I'll keep reading unless someone knows but I suspect it will be product specific.

The coating will fill the imperfections.

 

[CNGsaves]

Wow, with all that concrete the garage will be a bunker in itself !!

Would have been oh so cool to make a 2-story garage with steel beam roof and another layer on concrete for 2nd floor up above (ie drive in long ways to lower garage using contour of ground . . . and have upper garage be drive straight in). Thus, house would be set back farther and a breezeway or carport would be up front.

Thanks for sharing and would be helpful to know general area or country you are located.
Update GJ Profile.

Good luck and keep the pictures coming.

 

[Scsmith42]

Re: Cleaning the surface of the concrete

Is all concrete like this?



]

Only the concrete that is not properly vibrated during installation...


Scott

 

[C2 Turbo]

Vibrated?

 

[wsettle]

are you referring to a Air Gap Membrane**

Thanks for the link. I've seen several membranes types and have been looking at one much like the one in your link. It's made by firestone, no dimples, and basically looks like a rubber inner tube. It comes in 12' and 15' lengths.

 

[wsettle]

In your garage view picture, it looks like your house windows are just above the garage roof. The windows better be wrapped real well or they/and wall will rot from all the splash back you will get. Just an FYI from other house repair experiences.

Thanks for the tip and it's something I didn't think of. I just added a bunch of windows to the rendering to get a feel for what they might look like. I'm still playing with wall height and roof pitch of garage to find the right size windows and placement. They have southern exposure so looking at overhang length as well.

 

[wsettle]

Wow, with all that concrete the garage will be a bunker in itself !!

50 yds so far

 

[wsettle]

Re: Cleaning the surface of the concrete

Only the concrete that is not properly vibrated during installation...
Scott

I think you are right. There were some honeycombs as well which indicate the same I believe.

 

[wsettle]

The coating will fill the imperfections.

Can you recommend a product that you have used?

Thanks!

 

[Scsmith42]

Vibrated?

Standard concrete placement techniques require that the mix be vibrated after placement. Usually you use a Wyco or similar ******** ( but there are some units available for shallow pours that are driven by an electric drill).

Plunges are made in the pour on 9" - 12" centers for about 3-5 seconds each. It is very important not to over-vibrate as you can cause the aggregate to separate from the mix and weaken the concrete.

The vibration helps to remove any air pockets present in the placed mix. For aesthetic reasons it us always a good idea to vibrate along the edge of any forms.


Scott

 

[hockey88fan]

Can you recommend a product that you have used?



Thanks!

I had a contractor do mine, it went on real quick, dried to a thick consistency, filled and leveled all the bumps and holes. He paid particular attention where the wall met the foundation.

 

[St-rider]

In your garage view picture, it looks like your house windows are just above the garage roof. The windows better be wrapped real well or they/and wall will rot from all the splash back you will get. Just an FYI from other house repair experiences.

If applicable, snow build up will also be an issue.

 

[RickP]

Nice looking house! That's a tough slope to build on and it looks like you've really thought about the design.

On my house, the contractor used pink rigid Styrofoam to protect the black tar waterproofing. I don't think you need the membrane if you use a nice thick waterproof coating. My foundation was built like that and it hasn't leaked at all in 9 years. You certainly have enough slope for good drainage! Just make sure you address the drainage on the uphill side of the foundation and you should be fine.

Did you put a sump pit in your design, along with perforated pipe along the outside of the foundation wall? That's the real key to a waterproof foundation. With that slope, you probably don't even need the pit - you could just run the pipe out to daylight. You have to assume that water will hit your foundation wall and it will be under pressure from the soil around it. The key thing for you to do is give the water a better place to go - into the pipe rather than into any small imperfections in your waterproofing. That system is a lot cheaper than an external membrane.

I don't think you need to do all that surface prep work. Just knock off the really high spots with the grinder. The black tar will fill in the pin holes and cover the ridges left by the forms. You could probably finish the grinding in one day - any more than that and you're trying to make it too perfect.

 

[wsettle]

No sump pit since the water only has about 30' to go before it's below the grade line of the lower level. Once I pour the upper and lower slab, I will slope the ground 1" every 5' so water will move away quickly. I will also be installing a french drain behind the retaining wall and storm shelter and around the entire house and then drain below the lower level. I will add roof gutters as well but haven't figured out how they will route yet.

The great thing about building on a slope is that the water doesn't hang around very long. However, building on this slope has been difficult from the get-go but I think I have the hard part behind me which was the excavation and concrete work for the footings/foundation/storm shelter.

About the surface prep, I do tend to want things just so (aka perfect) but I am beginning to understand that I really only need to knock off the high ridges and sharp protrusions. The 4-1/2" diamond double cup wheel I bought can grind the concrete fast so I agree that it won't take long to smooth it out. The concrete is still green so will wait until after the holidays for it to cure before preping the concrete and waterproofing it. I've been told to wait 30 days before back filling but will probably wait more like 45 days since it's been cool weather. I've 150,000 lbs of back-fill to install behind the wall so I want the strength to handle any lateral wall pressure from the back-fill.

A friend gave me about 20 sheets of the 3/4" tongue and groove pink dow styrofoam that was left over from his siding job. They wrapped his house in the stuff before residing. I was planning to use 2 layers of it between the waterproof coating and the backfill. I will need to purchase a few more sheets to do the job or is there a better product to use?

Styrofoam is styrofoam, right?

 

[wsettle]

If applicable, snow build up will also be an issue.

I'm in central Arkansas so we don't get much snow. 1" would be an unusual "storm" but we usually just get dustings. Thanks!

 

[wssix99]

Nice house!

Do see a lot of ground water at the base of your concrete walls when its not raining? If not, then you should stay relatively dry except when it rains, which would probably make a fancy membrane coating, etc. overkill. I'd think you would be fine with a simple rolled-on coating if you stay dry in the dry.

Your point about the french train is key since your walls form a "C" shape that could trap water coming down the hill. That water pressure will damage the walls, so you'll want a pathway for water to get out of that trap.

Standard concrete placement techniques require that the mix be vibrated after placement.

Some concrete is self-consolidating and doesn't need vibration. I'd expect that foundation companies would use a mix that doesn't need a lot of mechanical vibration, especially for a basic wall that isn't taking a lot of weight.

I was surprised at how many bug holes it exposed. Is all concrete like this?

All concrete has air bubbles in it, called air entrainment. In general, they are a good thing: http://www.cement.org/cement-concrete-basics/working-with-concrete/air-entrained-concrete

Your bugholes don't look like they would be a problem, other than from an aesthetic standpoint. They would need to be greater than 1" to cause issues: http://www.cement.org/for-concrete-books-learning/concrete-technology/concrete-construction/bugholes

I'd also expect that a roll-on coating would fill them without any additional intervention.

 

[RickP]

A friend gave me about 20 sheets of the 3/4" tongue and groove pink dow styrofoam that was left over from his siding job. They wrapped his house in the stuff before residing. I was planning to use 2 layers of it between the waterproof coating and the backfill. I will need to purchase a few more sheets to do the job or is there a better product to use?

Styrofoam is styrofoam, right?

That pink stuff is what I was thinking about - I don't think there's anything special about different brands of styrofoam. But there is a difference in the R-value of the low-density stuff. Just make sure you get the high-density kind - you probably only need one layer.

I just looked at some old photos and realized that the contractor used pink fiberglass on my house:

You can also see the black spray-on waterproofing on the left, where the pink fiberglass hasn't been applied yet.

 

[wsettle]

I don't see much water accumulation at the footings even during a hard rain. Ir runs off the hill as fast as it comes down. In the first few pics, you can see where I put a 6" pipe under the storm shelter so the long retaining wall will have a french drain running the entire length plus I'll have a french drain around the storm shelter and stairwell that will tie into the long drain then release it over the hill. So you may be right in that the membrain is overkill. Do you have any recommendations on a brand of roll-on coating?

There are so many to choose from.

I have learned a lot about concrete from the concretenetwork.com and simular sites but I have not seen cement.org yet. Thanks for the links on bugholes and air entrapment. Great information!

 

[wsettle]

I just looked at some old photos and realized that the contractor used pink fiberglass on my house:

The pink stuff I have is high density and I think it's a closed cell syrofoam as well but not certain.

Interesting about the fiberglass used on your walls. I would think that it would let water pass through and may even be a benefit over syrofoam to let water move down the wall quickly.

Options, options... man, there is a world of options

But I already have the foam and seems to be a typical application for it so I'll probably use it.

Thanks for the pic. Your foundation wall look complex. I'm sticking with two basic rectangular boxes and attic trusses to keep it simple. The wrap around porch will make up for it in comfort and style

 

[RickP]

Interesting about the fiberglass used on your walls. I would think that it would let water pass through and may even be a benefit over syrofoam to let water move down the wall quickly.

That's a good call - I hadn't thought about the water moving down the walls, but I'll bet you're right about that. I don't think the pink stuff provides any real insulation value for my basement -- it's really just to protect the black tar film from being damaged by the soil. For me, any insulation value will be on the inside of the foundation if I ever get around to finishing the basement.

Thanks for the pic. Your foundation wall look complex. I'm sticking with two basic rectangular boxes and attic trusses to keep it simple. The wrap around porch will make up for it in comfort and style

You're right about the complexity -- that's why we went with block instead of poured walls -- the forms would have been a nightmare! I think you were smart to go with concrete, especially if you're in tornado country. Your wrap-around porch sounds great -- I wish our design had one of those. But we did put in a small screened porch to make up for it a little bit.

 

[wssix99]

Do you have any recommendations on a brand of roll-on coating?

Unfortunately, no. I would look primarily at warranties and would expect a rubberized coating will probably hold up in the long run.

I don't think you need to worry about water infiltration so much, but having a coating there, should keep your garage and storm shelter spaces less damp. Since you don't have standing water, there's probably no need to use the stuff everywhere - just where you'll have back fill up against occupied space.

I have learned a lot about concrete from the concretenetwork.com and simular sites but I have not seen cement.org yet. Thanks for the links on bugholes and air entrapment. Great information!

The Portland Cement Association is the premier trade group and - IMO - the best source of technical info. They aren't out to sell a particular type of cement product over another - just to sell cement/concrete over other building materials. (So, if you are already sold on cement/concrete - they have great information. If you are trying to decide between concrete and something else, they might be a little biased...)

 

[wsettle]

The concrete has been curing for over a month now and it's time to waterproof and backfill. I've chosen to use a locally obtained product called Masterseal. It's a BASF product called HLM-5000 roller grade.

We have ground down all sharp edges, cleaned the surface (lightly ground off all form residue) as the instructions specify. However, the instructions also specify to:

Clean metal surfaces to bright metal and prime with a quality rust inhibiting metal primer followed by MasterSeal P173 or P176

Unfortunately, the supply house does not carry the P173 or P176. They told me that the ties should have broken off below the surface of the wall so there would be no exposed metal, but none of my ties did. All of them had to be ground off flush with the wall.

So my question is, does anyone know of a suitable primer I can use (like rustolium) or should I not even worry about priming the metal?

I guess the problem might be an incompatibility of the primer and Masteseal. I'll test a few interior wall areas with and without a primer this weekend to see if any of it works before we start the big job of waterproofing next week.

Please let me know if you have any suggestions and thanks to everyone that has provided help so far.