Core drilling an a/c hole in the house

[Tigercubrider]

i have a portable a/c unit that uses a tumble drier type hose to exhaust it's warm exhaust.
It was previously used in my gf's flat, upstairs, with sash windows. So I made a panel with hole and used the sash to trap it.

I now want to use it in my house. I cannot really core drill through the front wall but originally the house had a porch built so that the front door was recessed from the building line by about two feet- and four feet wide or so
Later, a single glazed multi-panneled glass and wood porch door was added to the building line
So I have a piece of wall in the porch that was an external wall and is now leading into a porch which has two small French doors, and a similar 12" wide panel on each side

My idea is to drill into the sidewall/ return and exhaust into the porch area, then duct this a couple of feet to the front and through a wooden panel replacing one of the glass bottom panels.I would box the duct in and apply insulation inside the box

My concerns are making the house cold in the winter
I could make the pipe removable so that the whole box was filled with insulation and plug the internal hole with a foam plug.
Comments?

 

[mattylad]

We need pictures.
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Nooo, not of the porch - your GF... lol
Maybe your GF in the porch?

So your planning on taking the exhaust and filling the porch with it? or are you just passing through the porch with the pipe and venting outside?

Yes insulate over the pipe as much as you can where it travels through the porch (so consider this when sizing the box - do not just do it to the top of the pipe) and a plug sounds a good idea if you can make it removable, long lasting and good looking.

 

[Tigercubrider]

I will try to do pictures (of the porch)
The idea is that the temperature inside the porch in mid winter is far higher than outside, so plugging the wall that the pipe exits from the living room to porch will present less of a thermal challenge
I have access to stuff like bandsaws so I could fashion a round plug out of good insulation material or "cast " one with expanding foam in situ with a couple of lubricated polythene bags
I can make another to seal the wood that replaces the glass panel but at a guess any wood that contains an exhaust flap will still be more thermally efficient than the glass

 

[foxhole]

Just core drill straight outside at most convenient point , short as possible , cowled vent will prevent any backdraft . Very little thermal loss as no air movement when turned off.

 

[rsgaz]

"cast " one with expanding foam in situ with a couple of lubricated polythene bags

Did you attempt this @Tigercubrider ?

I need to plug up the duct I put through the wall for a portable air con, also. I already made an MDF cover for the inside so it's air tight, but I want to make something better so it doesn't turn into a wasps nest or let noise/cold in. I can't stand fibreglass insulation, so I don't want to just stuff some of that in there.

 

[SFK]

Rsgaz,
How about fibre glass insulation in a black bag, then stuffed into hole?
Or if you see any Kingspan/Celotex offcuts, make a bung out of that.

SFK

 

[rsgaz]

fibre glass insulation in a black bag,

I see that above false ceilings quite often, it's still itchy/dusty and annoying as hell, even in a bag!! I really don't like it, sorry!

Kingspan/Celotex offcuts, make a bung

Yeah, that's what I've been pondering over for weeks. I have a rectangular duct to fill, which I want the bung to go all the way to the outside vent, so my bung needs to be about 200 x 56 x 350mm. I'm not sure how well/accurately I could plane(or belt sand) down a thicker piece to 56mm. I want it to be a pretty tight fit, but then it would be very tricky to get back out when I want the air con. I can't win!

I was hoping to 'cast' some rope into it, to give me a handle to pull it out with. Just hoping someone else had tried it first to see whether it was a disaster or not!!

 

[SFK]

Understood regarding glass fibre.
But if you hate glass fibre I would not be sanding Kingspan/Celotex offcuts for the horrible smell it gives off and fear of dust damage to my lungs.

My suggestion:
Get a saw (or I find a bread knife works well) and cut the large block Kingspan/Celotex into a 'bung' that is the size of your hole.
Then wrap bung in duct tape so it fits tightly in the hole, keeps its shape, and does not drop any Kingspan/Celotex bits.

Make a handle from the duct tape that will fold flat when bung is in place:
- Use long length of duct tape, put a (guess) 10cm length of duct tape in the middle of the long length, sticky side to sticky side.
- Make this non sticky section into a loop hand hold when you stick this long length around your block.
- This duct tape handle section will then fold flat when not needed.

True Blue Peter, but you will not see it.

SFK

 

[SFK]

...and put a handle on both sides for the day that you push it in the wrong way round.
:>

 

[Tigercubrider]

No not done it yet. Next year maybe
As above I'd probably make something out of celotex , cut to size and glued up.
A hole right through for a handle, rope/doweling and a bit of ply on each side so it won't break
If you line the hole with two layers of bin bag or slightly stronger poly, it will act as lubricant to remove the plug

 

[arkie]

Make the wood bung smaller and staple on rubber door seal around it so that its an air tight fit.

 

[rsgaz]

I gave it a shot yesterday, I had left it over 24hrs to cure, and ended up with a disaster!!!

I didn't cast it in the duct in the wall, I'm not that stupid, I had some leftover duct to use.

I lightly oiled the insides of the duct, so it wouldn't stick to the mould, but something has gone really wrong with the foam! Does it react badly with oil maybe? Most of the inside is just hollow and most of it hasn't set either...



I was pretty sure all along I would have to cut the mould open to release it, maybe 5% of me thought I would just be able to slide it out!! But this cheap foam is different to foams I have used in the past, especially for a fire foam. Even the parts that have set, still seem squishy and the bubbles are too big. I'm used to it ending up very firm, much closer to actual Celotex firmness.

All I have salvaged is a 4cm deep bung, when I wanted over 30cm!



Think I'll just duct tape some Celotex offcuts to the back of this. I like the way it turned out on the front!!

 

[arkie]

I think the way to do it would be in layers, letting it fully set up before a new layer.

 

[Tigercubrider]

It needs moisture to cure, you should fill slowly, (maybe from both ends for speed?) and use a plant mister to apply water- maybe spray the mould first? So water/foam/water/foam etc.

 

[rsgaz]

After all that, I ordered some 'cut to size' fire retardant foam and made a duct tape handle/handbag with it!!

That goes in first, nearly up to the external vent. Still going to keep and use the plywood/rope/red foam bung next, then a painted and bevelled MDF cover screws on inside over the hole.