Integral Garage Conversion - Structural Engineer Report

MOPI

Hi, I'm looking to remove part of a double skin wall between my integral garage and kitchen/diner to create some more living space.

I have obtained a structural engineer report, which has recommended that 50cm of the existing wall is retained to load padstones onto and 2 steal beams are . This will create a pillar in the space of the room, in addition to the dropped ceiling from the two steal beams. I'm a little bit disappointed as the wall being removed is only 2.8m wide, although I understand that other factors affect the structural requirements. The 50cm wall sticking out will unfortunately create quite an awkward space in the room

I obviously want to ensure that the conversion is safe and compliant but at the same time I have reservations that the structural engineer has been ultra cautious and therefore this has created a necessity in their view for 50cm of the existing wall to be retained. 

I'm looking for advice on what to do next. Should I contact the structural engineer to enquire if anything can be done to minimise the wall sticking out (seems unlikely!). Alternatively, I was maybe thinking of getting another structural engineer report but I'm put off by this option because of the cost involved.

Any advice would be gratefully received!

Doozergirl

It's perfectly normal.  You can do things to minimise the size of the pier, but the cost increases massively.  When the pier is that large, it often includes an original corner of the house. 

I've designed around so many of these now, it is possible to hide them quite effectively behind larder unit doors, or simply use the wall as a break between different types of units - so a worktop run turns to a bank of larder units.  They can also be quite handy places to have plug sockets -when you have a toaster or a mixer that wants worktop space, they like to have a corner to live in. 

I don't have your floorplan or I'd try to make suggestion.

Bendy_House

Hi MOPI.
This pillar will be 500mm wide, but I presume will only stick OUT by 150mm or so?
As Doozer says, a plan would help us to visualise the options.
The second skin of this wall - the house's - I presume that's concrete block too? So I wonder if this can be used as the main support for the steel? Whatever extra needs to be added to this - 50-odd mm - could then be disguised, tho' it would mean losing this from the whole wall if you did - worth it?
It would also be a LOT more work as this extra 50mm would, I imagine, need to be structurally incorporated into that house skin.

Another option could be for a vertical channel to be ground out of the house's wall and a steel post built in. We had one of these in our new extension, and it was only 4" square. Again, more work, and it would stick out a bit, which would again need disguising, tho' probably not to such a great depth.

We did, tho', have to accept two central stick-out pillars along the main walls in order to carry a 6m steel, but there was no issue for us in restricted width as a result, and it's become a nice feature as each carries a tall column rad.

Doozergirl

Bendy, it will be 500mm deep.  You don't need 500mm of bearing for a 100mm steel. Presume it will be 300mm wide if it's a cavity wall.  

I was guessing it was at the corner, but perhaps the SE wants one in the middle of the new space because the requested opening is so long that it would require a steel of ridiculous depth, so they want to break it into two.  

Either way, it's all about designing your layout sensibly according to the structure of your house.   Building an island around it is another option, or zoning the space to flow around it.  No idea without drawings.  

Bendy_House

Doozergirl said:

Bendy, it will be 500mm deep.  You don't need 500mm of bearing for a 100mm steel. Presume it will be 300mm wide if it's a cavity wall. 

That's just confused me :-(  I really don't understand.

This is a double-skinned wall. The garage skin is being removed, but they need to leave a 500mm wide section of that wall (I presume it's somehow bonded to the house's skin or else it would be free-standing?!), and this remaining 500mm-wide pillar will be sticking out into the room by its wall thickness, presumably ~100mm? To take a padstone would require that to be a min of 150mm?  So the intrusion into the room would be 'only' 150mm?

Or, remove a block from the house's skin in order to slip in the steel and padstone = 100mm, but the pillar would need building out by a further 50mm (surely there's a clever way of doing this?). So the 'intrusion' into room space could be reduced to ~50mm, I'd have thought?

But I've clearly misread summat :-)

Doozergirl

I can't interpret what you are talking about.  

If you are attempting to remove a wall at the corner of the house then you need to leave a significant section of the corner in to stop the lateral load on a house from collapsing it.  

There's also a rule of thumb that you can only remove 2/3 of an entire wall at ground floor level without going down the route of goal post steels.  

You only need a 150mm bearing for steels but you need more house left than that.  

MOPI

Thanks for the responses, really appreciated.

I've attached the floor plans to give you an idea of what we want to achieve (on the current floor plan the room at the back of the property is labelled as 'living room' but is in fact the kitchen/diner area. The worktop space is to the right of this area and the dining bit is set next to the wall that is being removed. 

We have verified that the wall is double skin from removing a small piece of ceiling and drilling through. 

We've been advised that the 500mm won't be recessed at all into the wall so it will be 500mm pillar into the room and then that will need to be boxed in etc so maybe pushing 600mm. 

Any further assistance on this would be greatly appreciated. Thanks!

Doozergirl

What are you going to use the garage for when it's all finished? 

What are the existing dimensions of the rooms?  Particularly the garage.  

And the lounge, actually. You're still planning to walk through the lounge to the rear?  

How does moving the stairs impact on the first floor? 

Where are your existing soil stacks?  I notice you're planning water and waste in two different areas. 

Section62

MOPI said:

I have obtained a structural engineer report, which has recommended that 50cm of the existing wall is retained to load padstones onto and 2 steal beams are . This will create a pillar in the space of the room, in addition to the dropped ceiling from the two steal beams. I'm a little bit disappointed as the wall being removed is only 2.8m wide, although I understand that other factors affect the structural requirements. The 50cm wall sticking out will unfortunately create quite an awkward space in the room

Looking at the plans I'd suggest your SE has decided the existing internal garage wall is also providing lateral support to the rear wall of the house (it amounts to a 'hidden' corner of the type DG is talking about). They are proposing a brick pier as a means of lateral support, which will double up as one of the bearings for the beams over the opening.

Have you got a first floor plan as well?  Does the first floor extend out over the garage, or does it stop at that internal wall?

Is there any possibility of extending to the rear of the property?  An extension properly tied into the rear wall could be a possible alternative to having a pier projecting into the kitchen.  Overall it may cost more, but could result in a much better finished result.  In my experience these situations tend to arise because someone (often the architect) has applied constraints to their thinking, rather than looking at all alternatives.  Often it is better not to fight the structure, but instead to work with it.

Also, have you checked whether you need planning consent for the alterations, and could you meet any requirements (e.g. replacement parking)?

Bendy_House

I can confirm that I completely misunderstood where this steel was going. . :-(