Advice regarding connecting Airing Brick for new porch

lokz

Hi,

For our new porch, the airing brick needs to be extended. Currently there is about 8 mm space under it (1 brick ) and about 4 mm space above it . Looking online gives me multiple options. can i use a straight duct to connect to the outer side. or should i definitely go for a z duct as in the attached image. some of the images are attached. Appreciate any advice. The porch pad will be updated with proper insulation ( 70 mm phoenolic board as I have some left over of it which fits the porch) and thinking of screed with electric underfloor heating coil and LVT on top of it .

FreeBear

If you go for a Z-Duct, you need to ensure there is some way for water to drain out at the lowest point.

lokz

https://forums.moneysavingexpert.com/discussion/comment/81960199#Comment_81960199

Didn't think about it. Thinking of a straight pipe which slants slightly downwards to the outside of the porch. Hope that should be okay.

WIAWSNB

Use a 'flat' profile duct, and it shouldn't encroach on the insulation or concrete slab excessively.

Any mileage in it elbowing as soon as it leaves the original vent position, and going out the side of the porch close to the house wall?

lokz

@WIAWSNB , Did not understand what you meant by the below

"Any mileage in it elbowing as soon as it leaves the original vent position, and going out the side of the porch close to the house wall? "

WIAWSNB

Isn't my wonderful diagram clear? 😭

Instead of taking the duct straight out to the front of your porch, make it take a right-turn immediately as it exits the existing air brick, run it tight along the front of the house, and out the side of the new porch next to the house front.

It would require drilling out an air brick there, but I don't see one in place at the front of the new porch either.

Have I misunderstood the layout?

lokz

https://forums.moneysavingexpert.com/discussion/comment/81960459#Comment_81960459

Thanks . Understood now. after some search thinking of using this to replace the existing airbrick with a Domus Airbrick reducer ( https://www.internet-electrical.co.uk/ventilation/fan-accessories/domus-60mm-x-204mm-flat-channel-ducting/domus-957-system-125-white-airbrick-reducer-width-204mm-height-60mm-to-width-220mm-height-90mm ) and there are other parts from the same Domus range to connect it to side of the porch.

Unfortunately inspite of telling the brickie that i need a airvent hole they have built it without one.

WIAWSNB

I am still not clear about the layout, but assuming it's as I imagine, and given that a new air brick needs to be allowed for somewhere, and given the front of the porch has nice decorative brick, I would personally go for my plan if it's less visually obtrusive. It should also have less effect on the slab/insulation layer.

Yes, that reducer would appear to be suitable to connect it to 'flat' ducting.

Section62

https://forums.moneysavingexpert.com/discussion/comment/81960391#Comment_81960391

Any mileage in it elbowing as soon as it leaves the original vent position, and going out the side of the porch close to the house wall?

Having it that close to the house wall isn't a great idea structurally - the interface between the old build and the new build is where any movement is likely to show up in the form of cracking, and making an opening there for the air vent will make the wall weaker in exactly the spot where weakness isn't wanted.

Given this will now be retrofit it would be better to put the vent where the least hammering has to be done to make the hole…. if the opening at the side is where a window is going then that's where I'd duct the vent from, if possible.

lokz

@WIAWSNB I am having the entrance door with a side fixed pane on the side of the porch and on the front of the porch which is parallel to the current front door, the space will be filled with a full length fixed pane. you are right about the layout.

@Section62 I already made the same decision. I will be making a hole under where a fixed pane will be installed on the side of the porch .