# Core drilling hole in supporting pillar?

Please can you post a photo from the otherside of the beam looking back at the cooker? What size is the beam?

That's a poxy design and work. Who wants massive piers and deep downstands.

Anyway, you can cut your hole in the top corner of the steel above the sensor. Difficult but do-able

Or if the joists are running in your favour, up and over in the ceiling void.
Why you are saying that it would be a bit disruptive is beyond me, surely it's better than living with the alternative eyesore for ever.

Cut through the steel does indeed sound difficult. I never mentioned anything about it being disruptive but if you are referring to taking up the laminate floor, and sub floor, above just to run ducting seems insane to me.

There would be no "eyesore" if I could drill through the pillar as on the right side of it the ducting, and hole into pillar, would be hidden by a wall cupboard, and on the left side where the hole would exit and turn 90 deg to go through wall next to window, I would box that in. That boxing would be the only visible bit of the whole job.

As to the "design": where the steel runs there was an external wall with a window and the back door in it. That removed and the pillar that used to support the lintel above the window remained to support the new steel. As to the deep downstand the steel couldn't go any higher as the top of it meets the end tiles of the sloping roof of the house.

Here's what I mean. If the beam did not need a 300mm pier, it wouldn't have one.

Let's say the pier is 3m high. If it is 300 x 300, its' 'slenderness ratio' is 3000/300 = 10. With this SR, the allowable compressive stress
must be reduced by a factor of 0.89.
If the pier is 200x300, the slenderness ratio increases to 15, for which the allowable stress has to be reduced by a factor of 0.75.
Therefore, the load-capacity of the pier is dependent not just on its' sectional area, but on its' slenderness as well.

im not sure where the cooker is going -it seems to me the duct wants to be in the top corner where the PIR is hanging?

Unfortunately its a design error not thinking about the extract duct.

-I had a long heated argument with a client last year about a similar issue -they wanted a cooker hood in a 'cloud' above an island, but then werent happy when I said we would have to counter batten the ceiling with 4x2. They thought we could drill 150mm diameter through their 200mm ceiling joists

Let's say the pier is 3m high. If it is 300 x 300, its' 'slenderness ratio' is 3000/300 = 10. With this SR, the allowable compressive stress
must be reduced by a factor of 0.89.
If the pier is 200x300, the slenderness ratio increases to 15, for which the allowable stress has to be reduced by a factor of 0.75.
Therefore, the load-capacity of the pier is dependent not just on its' sectional area, but on its' slenderness as well.
But the pier is 300mm. If it didn't need to be, then it wouldn't be. It's that simple.

So the op can't effectively reduce it to 200mm by drilling a 100mm hole.

steel couldn't go any higher as the top of it meets the end tiles of the sloping roof of the house.
You've got at least 300mm of head to the ceiling, then a wallplate then the rafters and joists. Is that steel really over 500mm deep?

What I'm saying is that the steels invariably go up in the floor/roof void. That's the basics of design and you get a nicer job and no problems.

Too late now I know, but it's annoying to see stuff like this, and those massive piers being done by supposed designers.

But the pier is 300mm. If it didn't need to be, then it wouldn't be. It's that simple.

So the op can't effectively reduce it to 200mm by drilling a 100mm hole.
I think you're missing the point about how slenderness affects load-bearing capacity.

A pier 300 x 300 only 1m high will support - say - X kN before it fails by crushing.

A pier 300 x 300 30m high will fail by buckling long before it would fail by crushing alone.

In design of masonry piers, the greater the slenderness, the lower the permissible load for any given cross-section.

im not sure where the cooker is going -it seems to me the duct wants to be in the top corner where the PIR is hanging?
Unfortunately its a design error not thinking about the extract duct.

The hob will be about 1m to the right of that corner so, yes, ideally that is where the duct would go through.

The "design" process was get a company to design a conservatory extension which included knocking through the existing external wall. That is nearly completed and now that we have an idea of the overall space available we are planning the kitchen. So the "error" is mine I guess for not thinking to plan the kitchen before!

You've got at least 300mm of head to the ceiling, then a wallplate then the rafters and joists. Is that steel really over 500mm deep?

What I'm saying is that the steels invariably go up in the floor/roof void. That's the basics of design and you get a nicer job and no problems.

Too late now I know, but it's annoying to see stuff like this, and those massive piers being done by supposed designers.

I don't know how big the steel is but the pillar was existing from when the wall was knocked through. If they had demolished the pillar then what would they rest that end of the steel on?

Please can you post a photo from the otherside of the beam looking back at the cooker? What size is the beam?

I don't know the dimensions of the beam other than it is approx 3m long.

Pic from other side.

Start by converting to megaduct - you've only got 90mm to worry about then.
Drill a few holes to find out where the steel actually is.
If no other route through and hard to tell without seeing it but I would consider going through diagonally straight through to the outside from where the sensor is and "behind" the pier (but I'm quite good at drilling neat holes through walls). Or knock 20mm of plaster off the walls either side of the pier then take 90mm off the back of the pier below the steel. As you have said, the "pier" wasn't designed and built but was the remains of the existing wall and presumably is not actually 300mm deep but is just the end of a longer wall - in which case I doubt a 90x220 slot would do any harm.

If they had demolished the pillar then what would they rest that end of the steel on?
The external cavity wall!

That pier could have come off for a 3m beam. The beam would then go up and give a flush ceiling with the conservatory, instead of that awfull little double step thing.

And presumably there was some existing constraint forcing you to have the conservatory ceiling so low and flush with the frame head? Otherwise the whole lot would normally be raised.

I think you're missing the point about how slenderness affects load-bearing capacity.

A pier 300 x 300 only 1m high will support - say - X kN before it fails by crushing.

A pier 300 x 300 30m high will fail by buckling long before it would fail by crushing alone.

In design of masonry piers, the greater the slenderness, the lower the permissible load for any given cross-section.

No I see the point, but you probably dont see mine.

If its been designed as a 300 pier then it needs to be one all the way up. A pier is designed for the weakest criteria, and that is how thick it needs to be. It's no good saying check this or that, to see if that particular factor may mean it can be reduced with a massive hole, because one of the other factors will say it can't just as it said it can't be a thinner pier from the off.

But anyway, it's moot now as it looks like it never needed to be such a monster in the first place.

The external cavity wall!
The steel took the place of the wall. For it to go further "back" (I assune you mean to be a continuation of the still extant external wall) we are talking chopping into the top of the wall in the next room (behind where that sensor hangs). That is a tiled bathroom so pita finishing off.

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