# Forum More Stuff Go to Whoa!  Under House Excavation

## bloomers

Hi all 
Long time lurker first time poster.  
I have been doing an under house excavation for over a year now. It has been fun and it has been hard work. I am now at the stage of handing it over to a concreter. 
This is where I started  
Original brick piers  
A bit of steel  
Temporary prop in so I can start to remove the brick wall  
Wall removed. Header and supports installed. First two I beams installed.  
More to come when I get time 
Glenn

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## Uncle Bob

Looks like a big job  :Smilie:

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## Godzilla73

G'day, 
Hard work indeed, what do you plan to do with the space you've created? Is that an EH i spy under the clutter?

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## barney118

> g'day, 
> hard work indeed, what do you plan to do with the space you've created? Is that an eh i spy under the clutter?

  ej??

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## bloomers

It is an EH. I do have some EJ parts laying around. 
I plan to make the area into a workshop and storage. Hopefully this will leave the garage free for the EH restoration. I also have the following for the workshop.   
and this

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## goldie1

Nice!  When you get all those piers out and excavate to 2.4 meters  and put down a slab you will 
have heaps of room for the donor ute  :Smilie:

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## Swerve

good stuff  :Smilie:  more photos and keep on working

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## bloomers

Third steel beam in  
 forth steel beam in    
removing the first of the brick piers

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## CraigandKate

Good work mate, very good use of space there and I am really jealous of your mill and lathe!

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## bloomers

Ready for the first stage of excavation   
It was interesting to see a bobcat under the house       
Even more interesting when it can turn around      
excavated to the second last brick piers. Now need to fully support the cross beam and get the rest of the steel in.

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## sundancewfs

Great Work! 
I am so envious...... Oh to be able to dig under the house with a Bobcat!....  :Biggrin:

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## bloomers

Last I beam installed and the rest of the centre support beam   
centre beam support and join complete. more brick piers removed

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## Swerve

Wow some big progress here, you must be really pumped to keep going, good work. 
OK, now I realise the workshop if off to the side, I was hoping you could drive your cars in, now I see why not. Still at least this now means your garage is just that, cars only  :Smilie:

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## bloomers

Steel supports going in to replace the brick piers for an original beam   
getting ready for the bobcat return    
The bobcat has excavated to the last line of brick piers. They have been removed and the steel supports are going in.
There was a lot of hard rock to jack hammer.   
four of the supports cemented in  
Bobcat hit hard rock and could not excavate to full depth. Looks like I will get a good workout with the jack hammer.

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## Godzilla73

Looking good mate, had any dramas with movement upstairs?

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## Gaza

Maybe get 1 tonne excavator with hammer n bucket even dry hire beats jack hammer any day, this has to be in top 5 DIY projects on this forum ever

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## intertd6

Be careful that confined space has the potential to kill with CO poisoning when using combustion engined plant.
regards inter

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## bloomers

> Looking good mate, had any dramas with movement upstairs?

  I have not cracked any plaster work but I definitely have moved the floor joists during the process. There was some existing problems with the foundations when we bought the place. There was a lot of  floor tiles in the bathrooms and toilet that were cracked. There appears to have been some movement over time and some water running under the house at stages. 
In the photo below, just to the right of the front left brick pier, there is the edge of another brick pier made with a different brick.   
The extra pier can be seen between the two piers in the centre of the photo. I am not sure when the extra pier was installed but when we bought the place, there was a 10 mm gap above the wood on top of the pier and the joist.   
The water running under the house was caused by a concrete path that was installed with incorrect fall that allowed the water to pool at the house footings. I have ripped that path out and installed a path that falls away from the building and some drainage. Since then, there has not been any water coming under the external wall.

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## bloomers

> his has to be in top 5 DIY projects on this forum ever

  Thanks for that Gaza. It has been a lot of work, but this forum is full people doing great work.    

> Maybe get 1 tonne excavator with hammer n bucket even dry hire beats jack hammer any day

  The pictures that I have posted have not quite caught up with where I am at the moment. I had a concreter in to prepare the foundations for the slab. He had a excavator and they had to remove the canopy to fit through the garage door. Turned out that he did not have enough head room to operate the machine under the house. He did what he could with a bobcat but the rock was too hard in places.  
I am not sure what size the excavator was, I can check with the concreter. I think I will have to seek out someone with a smaller one with a rock breaker.   

> Be careful that confined space has the potential to kill with CO poisoning when using combustion engined plant.

  
Yes we noted that. With the garage doors open and the a fan it is not too bad. Cannot spend long periods though with a combination of dust and the exhaust. It is ok in the bobcat cabin, anything else, not so much.   Glenn

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## paddyjoy

Looks great, big job! Are you going to do anything around the perimeter to stop any future water getting in? Considering you have dropped the ground level could water seep in through the sides?

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## bloomers

> Looks great, big job! Are you going to do anything around the perimeter to stop any future water getting in? Considering you have dropped the ground level could water seep in through the sides?

  Yes, there will be a retaining wall, waterproof membrane and agi drain to stormwater

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## cyclic

> Yes, there will be a retaining wall, waterproof membrane and agi drain to stormwater

  Whatever you do, don't connect your ag drains to the existing stormwater drainage, run a separate drain, otherwise too much rain or a blockage may see you getting water pushed back into the excavated area.

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## paddyjoy

> Yes, there will be a retaining wall, waterproof membrane and agi drain to stormwater

  Great, our place is on a slope, partially excavated but there is no waterproofing so the walls do leak after heavy rain so make sure you get the waterproofing right!

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## bloomers

Getting ready for cementing steel supports  
Far posts concreted in and temporary props removed  
Preparing more support foundations  
Really hard rock here  
more foundations, not so much rock here

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## bloomers

Pile of dirt getting a bit big     
Had a truck load of dirt removed     
foundation holes certified. Three more supports cemented in.   
And two more this end  
Temporary supports in and three of the brick piers removed

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## bloomers

Getting the last steel supports in and cemented  
Temporary props removed  
He house is fully supported by the new steelwork  
Wanted to get an excavator to prepare the footings but the excavator was too big to operate in the confined space. It was mainly a head room issue. It was thought that a smaller machine would not have the power to break the rock. The operator used a bobcat to remove as much material between the posts as he could.      
I could not find anyone with a rock breaker on a small excavator. So it is jack hammer time.

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## dr renovator

My first reaction was 'crikey'! That is some serious steel work in there - how did you actually manoeuvre them into place and lift to the required height? Will be great to see the finished job and of course the EH restoration...

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## bloomers

> My first reaction was 'crikey'! That is some serious steel work in there - how did you actually manoeuvre them into place and lift to the required height? Will be great to see the finished job and of course the EH restoration...

  
The steel lengths were easy enough to move around by two people with the use of a trolley and an engine hoist. To get them in to position, I dragged/lifted one beside a row of brick stumps. I then inserted temporary supports on either side of the existing beam. I adjusted the supports to take the weight until I could work a hacksaw blade between the top of the brick support and the wooden beam. I then removed the top course of bricks and cut out the wooden beam. 
I then lifted one end of the steel beam and slipped in a milk crate. Then a bigger lift and slipped in a saw horse. In the picture below you can see the horses that I used. I also used some temporary frames made from pine studs. I lifted one end onto the frame and stabilised it. Then I carefully lifted the other end, moved it sideways until it was on top of the brick pier. Then it was just a matter of adjusting the position and then putting in packing on top of the pier, removing pressure from the temporary supports   
This photo shows the supports still in place after inserting the steel beam

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## jatt

Gee its certainly a project n a half.  Can sympathise with rock, the jack hammer is still getting a workout at my joint.

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## bloomers

The retaining wall will go behind the steel supports. So I need clearance for the 200mm blocks and at least 150mm for drainage.          
the pile is well over a meter tall  
No room to move 
had a truck load removed to give me some room   
there will be a toilet in this corner

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## Cecile

I have been completely blown away watching this amazing project.

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## bloomers

> I have been completely blown away watching this amazing project.

  Thanks Cecile. I wore out my wife's patience with the jack hammer though. I was taking two days (non consecutive) off a week so I could jack hammer while she was at work.

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## bloomers

Had the plumber in to do the drainage and sewage. Found the storm water squashed and replaced a section to fix it.   
Back filled after the plumbing inspection. Just need to re-lay the paving.   
Toilet, sink drain and agi drain for the retaining wall.   
Removed all the dirt. Still some work to do.   
The last pile of dirt. All ready for the final bobcat clean up.   
Ready for the concreter to take over.   
Marking out the starter bar positions for the concreter.

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## bloomers

All ready for concrete and inspection by certifier. The concreter knew how much work I had done to dig out this area. He rang me after the certifier had left. He said that I needed to dig out some more. I did not answer him, I was probably just processing the implications of what I was hearing. Then he said that everything was fine. I could have killed him, but I was just happy that it was approved.            
Finally I have a slab

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## Armers

That's awesome dude... I've been watching intently as I want to do the same to my house on day..  
But you're happy to finally reach that stage..  
Sent from my GT-I9300T using Tapatalk 4

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## firebug454

Wow! Subscribed...  :Smilie:

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## Swerve

Looking great, such a great feeling once the slab goes down, no more dirt !!!!!

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## Gooner

Wow. Consider me impressed. Great motivation. Lots of work in a relatively short time frame.

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## bloomers

Preparing for the agi drain and making sure that there is a fall to the southern corner      
Brickie setting up for laying the block wall      
Some of the starter bars needed a little bit of bending to make them fit. Apparently there was a lot of swearing involved.            
Immediately after this was done it pissed down for a couple of days and I saw a graphic example of the drainage working exactly as it was supposed to. The brickie was surprised to see my drainage preparation. He said that it is the first he had seen one with fall from one end to the other. Now I need to get the drainage finished and put the membrane on the back of the blocks. After that the brickie will be back to finish the retaining wall.

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## Belair_Boy

Great Job and a great space created, first class effort.  :Biggrin:  
I hope you had a celebration when the slab went down, it is a big achievement.
I will be cracking a few cold ones when my last slab is poured, that is for sure. 
I cant wait to see the final set of photos with the lathe and mill in place and swarf on the new concrete. 
Keep up the good work!!

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## Uncle Bob

:2thumbsup:

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## bloomers

Drainage complete. Membrane and coreflute  in. The brickie returns                        
Now I need to membrane and coreflute the rest of the wall. Put in the vertical reinforcing for the core fill wall and get sign off by the certifier.

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## Danny.S

Great job.   I'm really enjoying watching this one. You will end up with an awesome space.

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## bloomers

Backfilling the retaining wall with a 14mm recycled cement "rock"     
Boxing for the first cement cap               
Finished one end over the xmas break   
Now to start the other end

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## ChocDog

Mate, thats a brilliant job you've done!

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## SlowMick

Amazing work sir.  i hope you have a whole bunch of fun down there when its finished.  :2thumbsup:

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## bloomers

Now the rest of the cappimg                
had my plumber fix up the the pipework

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## Uncle Bob

> had my plumber fix up the the pipework

  I'd bet he was happy with the amount of room to move under there  :Wink:

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## whitey56

Hi Bloomers
I'm impressed greatly by your steel work and the amount of dirt you have dug by hand but Maaaate! wouldn't it been easier to move house.
In your first couple of photo's I thought at least the digging is easy but that didn't last long hey, I have done a few under hose excavations in my 15 years as a House remover, we used a guy who had a Massey 200 drott it was about 40years old and low, I said to him one day why don't you buy a new Drott his reply was nobody makes anything that low and  didn't want to loose work with a higher machine, the little Massey could dig though and just about everyone in the area used him for digouts.
I hope the guys who did the brick laying and electrical originally are out of the game their work is just garbage.
I love your Lathe that's the one I would buy if I ever get a lazy 3k or a good S/H Tiawanese of the same model, did that little Bandsaw cut the RSJ's a BS4 or 5 isn't it. 
Keep up the Quality work
Whitey

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## bloomers

> I'd bet he was happy with the amount of room to move under there

  Yes he was. He was also happy because he did it during that real hot spell of 40+ temps. Working under the house was a whole shipload better than outside work.

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## bloomers

> Hi Bloomers
> I'm impressed greatly by your steel work and the amount of dirt you have dug by hand but Maaaate! wouldn't it been easier to move house.
> In your first couple of photo's I thought at least the digging is easy but that didn't last long hey, I have done a few under hose excavations in my 15 years as a House remover, we used a guy who had a Massey 200 drott it was about 40years old and low, I said to him one day why don't you buy a new Drott his reply was nobody makes anything that low and  didn't want to loose work with a higher machine, the little Massey could dig though and just about everyone in the area used him for digouts.
> I hope the guys who did the brick laying and electrical originally are out of the game their work is just garbage.
> I love your Lathe that's the one I would buy if I ever get a lazy 3k or a good S/H Tiawanese of the same model, did that little Bandsaw cut the RSJ's a BS4 or 5 isn't it. 
> Keep up the Quality work
> Whitey

  The digging was easy to start. I thought it was going to be fairly easy. When it got too hard for the bobcat things went downhill fast. Got there in the end with a bit of work.  
The bandsaw is a BS5 and comes in very handy. I had the steel delivered cut to length. I have cut an RSJ with it before. There is not enough depth for one cut and the RSJ needs to be rolled over and finished from the other side.

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## Ronburgundy

Hi mate, very impressive work!
I have been planing to do something like this myself. I have a few questions that you might be able to help me with.
What size steel beams and posts did you use?
How did you know what to use?
Did you follow a set of guidelines or talk to an engineer?
when you said that it has a fall to the south are you referring to the Drainage pipe or the slab? 
cheers and thanks in advance

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## bloomers

> Hi mate, very impressive work!
> I have been planing to do something like this myself. I have a few questions that you might be able to help me with.
> What size steel beams and posts did you use?
> How did you know what to use?
> Did you follow a set of guidelines or talk to an engineer?
> when you said that it has a fall to the south are you referring to the Drainage pipe or the slab? 
> cheers and thanks in advance

  I started by engaging an engineer who did all the specifications and drawings. The beams are150 X 18.0 and the uprights are 90x90x5 SHS.
The fall to the south was the drainage.

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## phild01

Great project.  Looking through the pics, was wondering how you managed the moisture barrier under all the steel posts.  Did you place plastic under the posts initially and tape the final plastic layers to this?  Also wondering what size footings under each post?

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## bloomers

> Great project.  Looking through the pics, was wondering how you managed the moisture barrier under all the steel posts.  Did you place plastic under the posts initially and tape the final plastic layers to this?  Also wondering what size footings under each post?

  The footings were 500x500x300. I did not have any moisture barrier under the steel posts. There is a moisture barrier under the main slab. Are there any issues?

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## SirMe

I love what you have done and it is what I would like to do with my place. 
Have you worked out how much this all cost....... 
Did you get much internal damage inside in terms of cracks in walls, tiles or floorboards etc.....  
How much did the engineering cost?

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## phild01

> The footings were 500x500x300. I did not have any moisture barrier under the steel posts. There is a moisture barrier under the main slab. Are there any issues?

  Probably no issues but may depend on how wet the soil can get.  When I did the same thing I lined the post footing with plastic sheet and then poured.  After excavating the surrounding area, I placed the vapour barrier and taped and overlapped that plastic.  Vapour barriers are meant to be overlapped and taped so I believed this should apply under the posts as well.  I am curious as to how this is typically done by others.

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## Andiamo

Bloomers, I have watched this epic throughout, logged in then logged out then logged back in many many times. A great achievement and explained and illustrated so so well. Still not totally clear on how the timber to steel beam switch out went but got a rough idea. Assuming you had many stresses throughout but definitely didnt come through in the comments and posts that you made Great to see it near on completion. I'm happy for you, its some journey 
My interest is because of this below! *Look familiar?? * 
Some of the brick piers are not even touching the timber beams! 
But it is a great opportunity to build a car, boat, games and music room thanks to a sloping block and open access already almost right to the back of house although space height reduces the further you go back. Temp in this area is also significantly cooler so super hot day option. Drainage set up needs to be spot on as some water penertration as it is now but done right should be ok. Already a garage and workshop at the front with overhead height so starting point is good and pushback from there is very popssible 
Had quote up to $110k which is almost certainly what I call "full freight" based on working through steel costs, excavation and earth removal, block laying, plumbing, concreting and other so getting a second and possibly third opinion. May progress it in steps ie steel first, then excavation, then so on and spread the cost but suspect it may come in more around $75-80k based. Still it big bill but the area size and functionality created would make it well worth it. 
Anyway, thanks again for the step by step, live project. Has been a huge source of info and help, much appreciated.
.

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## bloomers

> I love what you have done and it is what I would like to do with my place. 
> Have you worked out how much this all cost....... 
> Did you get much internal damage inside in terms of cracks in walls, tiles or floorboards etc.....  
> How much did the engineering cost?

  I did not really keep a tally of the cost but a quick calculation I think it would have been around 35K. Big ticket items were the steel, slab and bobcat/tipper. 
I did not crack any plaster, but I cannot comment on tiles because they were already cracked and the floor boards already creaked. There was some existing issues with water running under the house etc. The excavation work has sorted these issues so now I need to renovate the bathrooms, en-suite and toilet. 
The engineer visited, designed and provided drawings for 1K.

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## bloomers

> Still not totally clear on how the timber to steel beam switch out went but got a rough idea.

  I laid the new steel bearer beside the line of the existing stumps. I supported the joists with a temporary bearer either side of the wooden bearer. I just put enough pressure on the jacks to raise the wooden bearer off the brick stump. As soon as I could get a hacksaw blade between the beam and the stump I stopped jacking. I knocked out the top course of bricks on the stump because the steel is taller than the wooden beam. I then cut out the wooden bearer. It was a bit hard sometimes because the joists were cross nailed to the bearer. Then through a series of lifting, temporary supports I raised the steel beam up to a height of the stumps and then on top of the stumps. That was the hard part and was made easier with a couple of mates. After a bit of jacking and packing the steel beam is in and the temporary beams can be removed.   

> Assuming you had many stresses throughout but definitely didnt come through in the comments and posts that you made Great to see it near on completion

  There was definitely stress especially when you are about to do something that, if it does not work, could be very expensive to fix.   

> My interest is because of this below! *Look familiar?? * 
> Some of the brick piers are not even touching the timber beams!

  Very familiar, but I only had one pier where the timber did not touch   

> Had quote up to $110k which is almost certainly what I call "full freight" based on working through steel costs, excavation and earth removal, block laying, plumbing, concreting and other so getting a second and possibly third opinion. May progress it in steps ie steel first, then excavation, then so on and spread the cost but suspect it may come in more around $75-80k based. Still it big bill but the area size and functionality created would make it well worth it.

  I got a quote from a builder for approx 130K. It would have gone over that because of the rock I encounted while doing the foundations. It took a long time to get the work done, but I did something every afternoon after work and at least 1 day on the weekend. As I said above, I think I spent around 35K and I have enormous satisfaction after doing the job. It is far from finished, but I am taking time off from this job to work on the jobs deemed more important by my wife.

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## garryaquagj

hi bloomers - hope you're still reading this great interactive blog. I missed - how deep is your agi drain? I thought you are excavating pretty deep, under the foundations of the original house - is the agi drain working on a fall to a pit? Or is the eventual drainage point low enough that the agi drain just falls into it with any seepage it catches? (I'm curious as I have to do a similar job, but much much smaller, and want to put a sump pit inside the foundations, and use automatic sump pump to pump any underground seepage up (2m) and outside the house walls. The (very old) house is on a steep block.
regards,
gj

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## bloomers

> hi bloomers - hope you're still reading this great interactive blog. I missed - how deep is your agi drain? I thought you are excavating pretty deep, under the foundations of the original house - is the agi drain working on a fall to a pit? Or is the eventual drainage point low enough that the agi drain just falls into it with any seepage it catches? (I'm curious as I have to do a similar job, but much much smaller, and want to put a sump pit inside the foundations, and use automatic sump pump to pump any underground seepage up (2m) and outside the house walls. The (very old) house is on a steep block.
> regards,
> gj

  gj 
There was already an agi drain for the existing foundation. You can see what is left of the original drain in the corner.   
This agi drain goes to the outside of the house and joins up with the storm water.   
When I re did the agi drain, I increased the size to 100mm and the drain was 250mm below the finished floor height in the corner below.    
I thought about a sump and researched the good old american basement. Most of the basements had sumps and the conclusion was not if it will one day flood, but when. Whether it is a failure of the pump or the backup battery powered bilge pump. If you have to have a sump, make sure that the design allows for easy access for maintenance. 
Glenn

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## SirMe

> gj 
> There was already an agi drain for the existing foundation. You can see what is left of the original drain in the corner.   
> This agi drain goes to the outside of the house and joins up with the storm water.   
> When I re did the agi drain, I increased the size to 100mm and the drain was 250mm below the finished floor height in the corner below.    
> I thought about a sump and researched the good old american basement. Most of the basements had sumps and the conclusion was not if it will one day flood, but when. Whether it is a failure of the pump or the backup battery powered bilge pump. If you have to have a sump, make sure that the design allows for easy access for maintenance. 
> Glenn

  Nice work I sent you a PM.......

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## rhunder1

Wow, great jobs doing. this is exactly what i am going to do soon. 
please post more detailed steps and precautions while you were doing that. 
thanks.

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## hrt22

Great job so far ,any chance of some up dates

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## duke149

Any updates?!  :Smilie:

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## levinracer

updates?

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## Prados

> Great job so far ,any chance of some up dates

   

> Any updates?!

   

> updates?

  ...probably still digging)))) 
I know how "easy" to do it by hands... big demo-hammer with the shovel bit is good but moving 20+ kgs tool around is a bit of a pain... in your back))) even after a few hours of digging.... after 1 week of hard digging you will be walking like a zombie!)))

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## duke149

Still waiting for the final photos  :Smilie:

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## Marc

I think he took the film to rabbit photo ...  :Smilie:

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## Invictus

Hey buddy 
Old thread I know, but just wanted to say congrats on such an impressive  job. I'm a couple weeks out from starting a similar project.
In  hindsight is there anything you would have done differently?

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