Retaining walls and patio

[EddieWalker]

Nice to see that you used chairs for the rebar. That's my biggest issue with concrete. Why didn't you install the rebar along the edges?

 

[Muhammad]

Nice to see that you used chairs for the rebar. That's my biggest issue with concrete. Why didn't you install the rebar along the edges?

No reason really. I guess we could have. Hopefully the combination of the rebar, big rock concrete, the thickness being average about 5", the sections only being 6', and using control joints will be enough the keep it in tact.

 

[goeduck]

You can avoid engineering on a 10 ft retaining wall in Washington if you go with those decorative ecology block sized bricks. But even then you still need a good base and a drainage plan (French Drain) and moisture barrier or you'll likely be sorry. Poured concrete 10 ft high retaining walls have their share of pitfalls too. I've seen some catastrophic failures with those in wet areas. No matter how you do it, a 10 ft high retaining wall is a serious wall that needs careful attention to detail.

I am planning it to be terraced with some planting space between, so two 5' walls, but it still needs engineering. The engineers are backlogged but I am in no hurry. Absolutely need drainage as I am on the low spot (on saltwater) of the slope. I already have a french drain around the house down to the water so it will tie into that.

 

[the old grind]

Zoysia? From Scotts.com

• Zoysia is a warm-weather grass that also tolerates cold weather well.
• This grass type loves sunshine (6 to 8 hours daily) but also grows well in light shade.
• Grows best in Southern and Transition regions.
• Can withstand heat and dry spells.
• An overall low-maintenance grass type that succeeds with little watering.
• Blades grow densely together making them excellent at withstanding high foot traffic and play.
• Zoysia grass grows best in USDA planting zones 6-11.
• The best times to plant zoysia grass are in late spring (once all chances of frost (?) have passed) to early summer. Plant when daily temperatures are consistently in the 70s. Zoysia planting can also be done in early fall, but make sure to plant at least 60 days before the first fall frost.
• Zoysia seeds typically germinate in 14 to 21 days under good growing conditions.
• Cut zoysia lower than most grasses—1 to 2 inches is a good height.
• Blades provide a beautiful green color through the spring and summer but will turn tan or brown when the grass goes dormant after the first fall frost.(?)
• Seeds germinate best when exposed to direct sunlight, so covering up seeds with a thin layer of soil or straw is not recommended.

 

[Muhammad]

Unnecessary driveway all poured. Going to cut the control joints this morning.

 

[EddieWalker]

The good thing about pouring on a slope is that they can't add too much water like a lot of them do when pouring a level pad!!!!

 

[Muhammad]

The good thing about pouring on a slope is that they can't add too much water like a lot of them do when pouring a level pad!!!!

Yeah the mix was a bit dry, kept it in place.

The finishers like that soupy pea gravel mix but it isn't strong enough for anything other than walkways IMO.

 

[Muhammad]

20 hours later.

Looks like the concrete poured from the first truck that had retardant in it already has hairline cracks. The concrete from the second truck without retardant has no cracking whatsoever.

I've seen some of the concrete guys on YouTube talk about this happening but no conclusive answers on the cause other than that they blame the mix. In this case using two different mixes gives an obvious explanation. It's the mix.

I didn't expect any issues since the steps were poured with even more retardant since there was a lot of hand work to be done on the finishing and it was almost 90 degrees that day. Yesterday was in the high 60s.

Not going to tear it up and redo it but this just goes to show you that many factors come into play.

 

[goeduck]

I am not seeing your initials scratched in along with a handprint anywhere.

 

[dragoneggs]

You can avoid engineering on a 10 ft retaining wall in Washington if you go with those decorative ecology block sized bricks. But even then you still need a good base and a drainage plan (French Drain) and moisture barrier or you'll likely be sorry. Poured concrete 10 ft high retaining walls have their share of pitfalls too. I've seen some catastrophic failures with those in wet areas. No matter how you do it, a 10 ft high retaining wall is a serious wall that needs careful attention to detail.

Maybe on your side... not around here. 4ft max.

 

[GSVette]

Maybe on your side... not around here. 4ft max.

4’ is the limit ( without engineering coverage) I’ve always found in the building code regardless of which side of the mountains you are on.

 

[Muhammad]

4’ is the limit ( without engineering coverage) I’ve always found in the building code regardless of which side of the mountains you are on.

Same. Also if there's surcharge, even 4' requires engineering.

 

[Cougsfan]

Maybe on your side... not around here. 4ft max.

I think it depends on the blocks that you use. I had a 10 tall foot tall big block wall at my last house that was not engineered, installed by a licensed contractor and inspected and approved by the building inspector. I did it because of that 4 foot rule, which we have too. They probably wouldn't let you do that with standard ecology blocks though, as their interlock is pretty unsophisticated. The wall was quite expensive, but less expensive than a less attractive engineered poured concrete wall that I was quoted.

 

[Cougsfan]

Perhaps it was considered a Pre-engineered wall?

 

[Muhammad]

I think it depends on the blocks that you use. I had a 10 tall foot tall big block wall at my last house that was not engineered, installed by a licensed contractor and inspected and approved by the building inspector. I did it because of that 4 foot rule, which we have too. They probably wouldn't let you do that with standard ecology blocks though, as their interlock is pretty unsophisticated. The wall was quite expensive, but less expensive than a less attractive engineered poured concrete wall that I was quoted.

By big block do you mean those blocks that weigh about 2 tons each?

 

[Cougsfan]

By big block do you mean those blocks that weigh about 2 tons each?

Yes, they are about 2'X2'x4' or thereabouts and are set by a track hoe. They interlock together quite tightly and have a choice of attractive patterns on the face. Some make it look like the wall is made from smaller blocks (that's what I chose), other provide the illusion of large odd shaped interlocking slabs. The top row of block is different and has a trench built into it where you can plant either grass or flowers. (I planted perennial flowers in mine) I have seen several other walls made of these blocks in my area set by the same contractor. Several are 10 ft tall if not taller.

 

[goeduck]

Yes, they are about 2'X2'x4' or thereabouts and are set by a track hoe. They interlock together quite tightly and have a choice of attractive patterns on the face. Some make it look like the wall is made from smaller blocks (that's what I chose), other provide the illusion of large odd shaped interlocking slabs. The top row of block is different and has a trench built into it where you can plant either grass or flowers. (I planted perennial flowers in mine) I have seen several other walls made of these blocks in my area set by the same contractor. Several are 10 ft tall if not taller.

Any pictures? Those large block walls can look real nice.

 

[the old grind]

The place where I get my pea gravel, CC, CL, etc has just put up a display/wall near one of their entrances. It's ~35' long, at least two rows high, has a vertical decorative face, and they have a corner on one end to show those blocks. If they're 2'x2'x4' that's roughly 5/8 yd. If a yd of concrete weighs ~2 tons, that's ~ 2400 lbs/block.

Anyway, don't want to side-track, and don't want to push our host for updates, but thanks guys for the discussion.

 

[Muhammad]

No more updates for now. Driveway is curing and a storm just passed through. Next steps are filling the spaces between sections with sand and stone then landscaping, and turf. Should be looking good by the spring.

 

[Muhammad]

After the forms were removed. Car on the driveway after a week of curing. Curing process was watering 6-7x per day.