Garden Room Ground screws. How we test for bearing capacity, Garden room construction video
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- Опубликовано: 26 апр 2021
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In this video I am with my mate Gil as we test the ground bearing capacity for a new garden room that I am working on, we do this to establish how many screws we need, what length screws we need and then the total number required to support our new structure.
By testing how much force it takes to remove the screw hydraulically we can do a mathematical calculation to establish the potential load, once we have established this we use a safety factor of 50% so if we feel that the loading is 2500kg we would safely assume that a load of 1250kg will be no problem.
Then we will work out the weight of the new structure allowing for live loads such as the effects of wind and the movement of people and placing of furniture etc, this will establish the minimum number of ground screws that we will need. Regardless of the minimum number we add screws where there may be a point load or additional loading so invariably we have a few more that we need.
Ground screws are a swift and economical way of forming a suitable foundation that is eco friendly and compared to a 1m deep mass filled concrete footing and brickwork and blockwork to dpc
Love how the car issue holding up the work was left in. Everything and anything happens on a site regardless of all your planning! Handled with class too
here's the daily compliment on how wonderful and informative the vids are! and super great for all the viewers that never seen this method.
Great video Robin! Found it very interesting indeed. Cheers.
Great video Robin, and wonderful sentiment about wishing you could respond to all of your commenters. Looking forward to seeing this project progres😎
Definitely need a detailed video this time on the ring beam attaching to the ground screws and the plastic ply :)
Excellent video mate 👍
Always love a good “pull test”
I hope we see you build this one from start to finish too!
12 under our 3m x 4.3m studio, about £950 from memory. Took about 3 hours but, when we came to start the build (SIP) it was running out by 13mm. Had to get them back, quickly resolved. Not much forgiveness with a SIP build but massive difference in U value compared to stick built.
More garden rooms. In my day we were lucky to have a shed and before that an Anderson shelter. Those little screw piles are brilliant for these type of buildings of limited weight. We get an even smaller version that you can use for ground level decks but haven't seen the sort you keep using. Got to be better than keep digging holes and concrete.
Robin can you do a detailed in depth garden room build series?
Love this channel keep it up
Very interesting thanks Boss
So interesting love the content
Interesting measurement techniques. Does (lateral) wind load play into your calculation? Thanks for the video.
I’ve been doing ‘pull tests’ for years!
Always get the same result Jason?.😵
Can’t wait for the vid with u splashing in the pool
"Everyones working from home". Theyre also drinking from home, most of these end up as pubs. 🤣🤣
Lot of people turning to drugs too! Very sad times
If you need more bearing surface area after the screw is driven, you could remove some soil around the surface level of the screw, add rock and compact it, and then pour a circle or square that would bond to the exposed screw threads.
If you're willing to pour concrete pads around the screws, the screws are redundant. The whole point of them is fast installation and low impact if you decide to remove them in the future.
Will you be the construction of this garden rooms in follow up videos to come Robin?
Hi Robin, tell to your colleague that better to twist off an extension cord during the and use protection garniture)
How much torque does the driver put out?
I would’ve holding my breath every pile hoping not to hit a big rock 🪨
Robin, I’ve been thinking about using these and I’ve seen they sell a hand screw attachment for manual screwing? Do you know if this is actually viable for an average garden or is it just for a garden with 6ft of topsoil
Don’t forget wind loading on a structure!
Dont forget the live load like snow
Lot if faith to put in a "should be" okay when you're putting in the ground spikes.
Nice job! What gearbox ratio do you guys use in this case?
How does pulling the screw out under tension test how much weight the screw can support under compression? Two entirely different forces acting in different directions !
How about to do a push test? Now we all know the wind wont pull it how about the weight of the garden house( large one i mean)?? After some time (winter or lot of rain) will it push it deeper or will it stay the same ??
👍
That couldn’t have been 2 n half tons pulling on that screw? Or was it 250kg? Great video anyway 👍🏼
After watching one of your earlier videos featuring ground screws I got Gil to come over and install screws (great work! all done in a morning) for a garden self build I started last month. 6x4m pitched roof timber building.. will be following these series closely as I build mine! Keep up the great work!
Edit: If you are doing a warm roof on this build and can share any details that would be great! about to embark on that phase of the build now...
We are doing a warm roof but not for a few weeks mate!!
@@ukconstructionthat's great, you might still catch up with me. I've got a fair bit of prep work to do still and I am doing it alone so snail pace... Cedar roof shingles arrive today! But have all the roof build up to do still, only rafters up atm.
That garden's the size of a football pitch!
Hi robin very interesting, but why not a traditional re-in-forced slab foundation, raft or even strip foundation? Surly after you have paid for these guys to come in with their rig and pull test it works out more cost effective?
Hi Jack there is no comparison to the price, I will do an alternative costing for one of the episodes of this build and compare, one thing here also is that the position of the room is about 200m from the road and it is land locked so other than a tiny excavator it would be a hand dig!!
How does a pull test tell you the downward force per screw.? I like the system, very good for poor access and uneven ground.?
Exactly, a pull test is not the same as a push test. A push test would be difficult off course, but it may be that the screws can handle more down force than the pull test reveals.
Can these ground screws be used on a house extension? One built using SIP panels like The Hup system.
Does that need planning permission or building regulation approval?
So the pull test, assume it sustained 1000kg would you assume that as your total max load so reduce that my by a safety factor?
Fast forward 2 years... Loads of summer houses and mancaves at right angles
Just wondering what exactly a pull test proves ... the building is sitting "on" the screws so I would assume most of the risk is screws somehow sinking when load is added ? might be stupid question 😅
The Pull Test proves the amount of tensile strength in the ground and the screw. If you imagine quite a light building, like a garden shed, in a very high wind, the wind is trying to roll the building over, so there is upwards pull force on the screws on the side of the building closest to the wind. This force can be greater than you think in high winds with slab sided buildings in exposed location and with certain roof shapes.
The pull test yeilds and means not much. But at least the yeild will be more than the load. On chalk or clay, your probably good. Gonna need a long one on sand and shale. Same shit realy, I like 'em. Piles are piles however you do them.
When you forget somebody's name and keep having to call them 'mate'.
Yes Mate!!!
😄😁
It’s a southern thing mate. 👍
Did you move the car alright?!!
So your using this to calculate the weight each screw can take before sinking ? in this video circa 2.5 tonnes each ?
Its called a pull test because it measures the amount of force needed to pull the screws out of the ground, ie the uplift from wind specifically during a major storm
What is the expected lifespan of the ground screws before decay reduces structural capacity?
Robin what is a ballpark cost for the installation of Ground Screws for a Garden Room of this size?
Well I suppose the average size room would be about 1500 to supply and install
classic 'bag over the extension lead' trick
Yes Clive!! I was waiting for that to be spotted, top of the class mate!!
It must have been quite wet! If it's only a shower you just turn it so the sockets are down. 😁
I never see you scanning the ground for Utilities , this is something yous do right
Think they just say fk it and go for it 🙄
I was legit taken aback when I saw the size of those screws. I thought it was a scene from Little Britain.
Mr macbeth is a naughty man
You haven't been on skillbuilder lately. All that finished now?.
These are the Swedish screws aren't they
Are you filming the garden room build robin?
Yes mate the whole thing
@@ukconstruction perfect look forward to the upcoming videos
Why pull test?
Out of curiosity wouldn’t a push test be more fitting for the intended purpose of the piles?
How would you anchor down the thing you're using to measure push
@@dharris85 my point is if there’s say 2 tonne structure sat on the piles it’s more important the piles don’t drop further into the ground rather than lift out - if you see what I mean
@@Smart-electrical A pull test will give the same indication of how solid the ground is though. Not sure if it's physically possible to do a push test, because you'd be pushing the testing machine up, and that would have to anchor to something and it can't anchor to air
To do a push test you'd need either a lot of weight that could be concentrated on one pile, or something like an excavator and a really heavy duty set of scales. 😁 Forces should be about the same whether pushing or pulling, as haz said.
the amount of time thats taken i could have the post holes dug
Well its getting the post holes past the building inspectors that the issue, we always have full building regs for our jobs as they are generally over the 30m2 maximum size that you are allowed to build without regs
Hi Robin
Does this company travel to Watford area?
I’m doing a self build garden room and I’m in need of ground screws being installed.
Possibly!! Ask him, it may depend on his work load
@@ukconstruction thanks Robin. I will!
I emailed you a couple of months back via you’re website asking for some advice on a garden room. I’m a carpenter by trade and wanted some insight. I know your busy but your opinion and advice would be much appreciated!
Take care my friend.
Ps whens this roofing square available 😉
great video but ! the load on the screwpiles is compressive not tensile , the weight of that building is going to push down on the piles
What happens if you think you have drains there how can you survey them before hand
We ask the client, or use the services companies to check their records and also we use a detecting device
@@ukconstruction ok thanks for the reply amazing videos
Hmmm
That's why the price of timber is so high - everyone is building garden rooms.
Would it not be easier to dig some footings?
Super pricey!!
@@ukconstruction fair enough
how much is that machine to drill them into the ground?
Why would you like to buy one?
@@ukconstruction yup
do car talk...could this be a garage?
thanks
Where did you get that weatherproof extension lead?
🙄
Hi Robin. You not getting back at Liam from 'Oakwood Garden Rooms' by building this garden room. I'm sure he was joking when he said he wanted to fight you
Did he actually say that!!
@@ukconstruction Have a bare knuckle with him Richard!!!
He was joking. Cant wait for build to start.
He was joking... he was getting fed up with people commenting that he wasn't a patch on Robin
@@jamesfarrer5087 Robin is a master craftsman. No doubting that
How do you know there are no services underneath
For cables - lick the screw? 😁
Global warming.In Australia we were told we would have endlees hot sumers, but we just had one of the coldest on record. We were told we would have endless droughts, but all our dams are full. There are more trees here,Canada and the US than there wass 100 years ago due to proper forest management.Enough tress grow every 15 minutes to build a new house. Im sick of all the fear mongering.