New House, New Workshop Build.

[deema]

@Spectric Its a really good point you've made. This is the first substantial building I’ve had built. My existing workshop is a steel clad building, built to office standards, but not with building regs as it’s an agricultural building with permission for what I do in it. We just shovelled out footings for the steel structure to what we thought was about right! It’s not moved, so we clearly got it about right. This is different it will be built under building regs, and I want to understand what it will cost before we put a spade in the ground. The foundations are the biggest unknown, the superstructure I have a definitive cost for, but getting out of the ground is usually the unknown. There are a number of different foundation systems, each with a different price tag. What I’ve decided to do is spend a little bit to get the foundations fully designed and optimised so there should be no surprises. I want the floor to be able to withstand the weight of small CNC machines as well as have the underfloor heating, making sure it doesn’t bend too much and crack the UFH pipes.
I might be throwing good money away, I don’t know, but the decision to go this way was done with a friend who has built numerous houses and now does this as standard as he believes it actually costs him a lot less to get the foundations built as a result.

 

[Spectric]

@deema if going industrial then use tried and tested / proven methods like we have used for decades, a concrete slab with reinforcement sitting on decent sub base material that has been well compacted. Like most things the finished article is only as good as the bits you cannot see, the one system I would say you definately don't want is block and beam that gives you the bouncy floor syndrome.

 

[Jones]

I would put your money into insulation and draught proofing possibly with a heat recovery and ventilation system , though I'm not sure how the filters for a mvhr will cope with a dusty enviroment. A heat pump and underfloor heating are a very capital expensive way to heat and if you insulate well they will rarely be used especially in a workshop where you don't want it too hot.

 

[Sideways]

But when he sells it on to someone who wants the workshop as artist / music / yoga / pottery / dance / pilates / tai-chi studio or whatever, the UFH might be a nice value added

 

[deema]

Just a quick update. The foundation design is almost done. The workshop is being built on made up ground with a distinct fall off towards the back.
The foundations will be stepped with a block and beam floor. We have been debating the floor loading requirements of the floor. Typical a garage is built to (I understand) 250kg/meter2. For the CNC tool room machines I hope one day to have we are increasing it to 750kg/m2.

To improve insulation I’ve decided to swap the garage doors and the French doors to become aluminium framed bifolds. Unbelievable a bifold is cheaper than a French door!! And about the same if not cheaper than a decent insulated segmented garage door. Not only do they have a better U value but they will let in more light and be rodent proof.

 

[Molynoox]

Just a quick update. The foundation design is almost done. The workshop is being built on made up ground with a distinct fall off towards the back.
The foundations will be stepped with a block and beam floor. We have been debating the floor loading requirements of the floor. Typical a garage is built to (I understand) 250kg/meter2. For the CNC tool room machines I hope one day to have we are increasing it to 750kg/m2.

To improve insulation I’ve decided to swap the garage doors and the French doors to become aluminium framed bifolds. Unbelievable a bifold is cheaper than a French door!! And about the same if not cheaper than a decent insulated segmented garage door. Not only do they have a better U value but they will let in more light and be rodent proof.

I'm surprised the bi-folds have a better u value than an insulated garage door; typically the glass is always the thermal weak point in an insulated outbuilding, by some margin. Maybe the garage doors have air leaks or something.

Martin

 

[deema]

Finally, after a bit of too and throwing we now have a design for the foundations and floor. It’s going to be step foundations with a calculated 46m3 of concrete required to produce them assuming the trenches don’t start collapsing when we dig them. The large (or should I say huge) picture window requires steel goal posts to support the roof.
The BiFolds offer not only enhanced utility of the building when we move on (or under the ground) but will also let in a lot of light which might make it possible to delete some if not all of the roof lights. The roof space can then be used for solar panels on the due south facing elevation……but that will probably be a later project when I’ve saved up again!!

 

[deema]

The diggers hopefully arrive on Monday to start in the foundations / install a new effluent treatment system which is the first job (we are on a septic tank) as I’m upgrading it whilst we have groundwork’s on going.

I have now to decide on what to put on the floor. I’ve upgraded all of the block and beam to take the machine weights along with how the underfloor heating will be done. However, with the BiFolds I need to ensure that the inside floor is level with the ground runner for the BiFolds so I can still ‘run’ things in and out of the workshop. With metal work there is always the risk (make that certainly that oil will be spilled in the floor, so I’m leaning heavily towards a resin floor. There is either the option of resin paint or a full flow pour resin resin floor. I’m not sure which. I suppose I’d really like a full flow pour resin floor but I don’t know how thick to make it or indeed which to select. Anyone have any experience / recommendations on what to do? It’s a hobby workshop, not industrial, but I want it to outlast me and also still look good in 20 years.

 

[Sideways]

Make sure you let the concrete dry properly before doing resin. My employers once bought a 3yr old factory with a resin floor in the machine hall and it had blisters filled with water that had been trapped in the concrete. We had it fixed and recoated. It was fun watching the guys walking around the floor spreading the resin wearing "bed of nails" plates strapped onto their shoes.
It makes for a pretty finish.

 

[Sideways]

Ground / polished concrete is really nice btw, but £££

 

[Jameshow]

If you put in a water supply you could sell it on as a granny annexe...

 

[NewbieRaf]

I’d be very interested to hear how you found the land? Did it have planning permission already? Are you doing a managed build I.e is someone (other than you) managing the whole build for you? Inc who the contractors are etc?

The wife and I watch a lot of the likes of grand designs and always seems nightmare ish

 

[deema]

It’s being built close to my house and is within my garden. It complies with permitted development rights so doesn’t need planning permission. I have a primary builder who is building it and will coordinate all the trades. Because of its size its under building control

 

[deema]

Time for an update. Stepped foundations didn’t work! After the ground surveys, structural engineer calculations, the simple truth was that at about 1.8m down we hit sand that was unstable, and the foundations couldn’t be dug. So plan B was required. We are now going to pile the site, in total 27 piles and then set the floor on top of the piles. Today, at long last the piling has started.

First off a photo of the footprint with the piling points marked out. Another surveyor needed for this! You can just see the caps of the stakes that mark the points.

And the piling, which should be completed in 3 days.

 

[Sideways]

Do they pile to a fixed depth or keep hammering until the resistance reaches a target number (aka piles stop going in any / much further when hit) ?

 

[deema]

The first metal tube is inserted into the ground. It has a bag of gravel dropped down it for the air hammer to hit against. Each tube is 1m long. As each tube descends into the ground the next is manually welded on to the last. They hammer until the tube reduces its decent into the ground to a certain length in a given time. In other words a measure of the resistance against the load is achieved. So far, it’s needed 3m to achieve this, and 9 of the 27 have gone in today.

The tubes will be filled with concrete.

 

[Phil Pascoe]

Easier and quicker to install a raft?

 

[deema]

Easier and quicker to install a raft?

The raft goes over the piles. A lot of the area it is made up ground / spoils from the house extension. It’s actually slightly cheaper than the stepped foundations.

 

[deema]

The build of the workshop seems rather fated! The piling should be finished in Monday, but due to the air hammer breaking down twice, that’s looking decidedly uncertain. Anyway, we have a few more piles in place just over half of them are inserted.

 

[deema]

Conduit and water pipe has been laid to the house. The conduit is future proofing and will enable a 3phase supply to be brought from the workshop to potentially air source heat pumps. I need power from the workshop as the house supply isn’t sufficient.

and back filled, the inspector was making his checks at the time of the photo.