Ventilating a Lean to Roof

[DrWazzock]

Getting a bit concerned about a build up of humid air under a corrugated lean-to roof above my cattle pen. Cattle getting a bit snotty like they have a cold. I opened up the boarding on each gable end up to allow a bit of flow over the tops of the walls but still feels too muggy in there. Not easy to open the top edge of the lean to roof as it's big 6 corrugated sheets that slide under the edge of a much steeper and higher roof. If I slide them away for the wall top then water will run off the steeper roof on to the cattle, unless I put another spouting up.

Is there such a thing as a vented sheet that can be used to replace a standard sheet to allow warm air to rise up through it with minimal rain getting down through it. I had thought of buying a few new fibre cement sheets and cutting slots on the peaks of the corrugations but they'd be greatly weakened. Anything purposely manufactured for this function?

 

[Badshot]

A lot of work, but I have seen a shed with the sheets laid so both edges are facing upwards and a gap in between lines of sheets.

 

[Cowcalf]

mushroom vents

 

[DrWazzock]

A lot of work, but I have seen a shed with the sheets laid so both edges are facing upwards and a gap in between lines of sheets.

I suppose I could take out every third sheet of the top row of the lean-to and being asbestos, put them on a pile.

Then cut new fibre cement sheets lengthwise every 2 corrugations and refit them on the roof in the places where have removed sheets, with edges of lengths upwards and gaps between up turned edges. in this way will still channel water running off the higher roof but let a bit of hot air out and not much rain in.

Could be just about doable without having to move every sheet.

 

[DrWazzock]

mushroom vents

OK but not easy to fit into a corrugated sheet?

 

[spanners]

Lift the top sheets off the roof timber slightly, so they are not resting on the next sheet down? --------____

 

[DrWazzock]

Lift the top sheets off the roof timber slightly, so they are not resting on the next sheet down? --------____

I suppose it would help a bit even though it would be halfway down the roof. There are only two rows of 10 foot sheets.

 

[Cjm]

If you can remove the fixings, it's possible to lay a batten between the sheet overlaps above the purlins and refix. Thickness is irrelevant, As far up the roof as possible. You could shorten the top row of sheets and put some new short sheets along the top...

 

[JNP]

What is the existing shed your fixed to used for? Is it fully sheeted on the sides? Is it possible to let the air flow into this shed instead of out the roof?

 

[Cowcalf]

OK but not easy to fit into a corrugated sheet?

they come fitted into a corrugated sheet. Other easy way I have used is just slide the odd top sheet down until you get desired air flow easily adjustable and mine have never been moved by the wind

 

[L P]

Have you thought of a fan and duct, may be cheaper and easier

 

[kmo]

Replace some doors with gates?

 

[Chuckie]

Have you thought of a fan and duct, may be cheaper and easier

I'm thinking the same, all our badly ventilated cattle sheds have fans in.

 

[multi power]

A lot of work, but I have seen a shed with the sheets laid so both edges are facing upwards and a gap in between lines of sheets.

very common where i grew up, but not sutible on a lean to, well not if the sheets need to go under the main shed to take water off

 

[DrWazzock]

I went up on the roof with crawling boards and as a temporary (probably permanent) measure I slid one sheet out from under the lowest sheet of the upper roof down to the next purlin, leaving a hole of about a square metre. This seems to have done a lot to create air movement along the underside of the lean to roof and might even be sufficient as the gable end is open at the other end.

I then slid a piece of galvanised sheet under the lower edge of bottom sheet of the higher roof to bring the water out away from the wall and wall top purlin. I might fashion a channel on the edge of this sheet to make it like a short length of spouting to guide the water to a down spout, though even with an inch of rain only 30 litres will get in off the upper roof.

Tonight things look and sound a lot better. The air is drier and fresher as are the cattle. If it goes on OK I won't slide any more sheets down.

The wall is stone so not easily holed to vent through into the next building.

I don't know why we didn't have this problem with cattle in here years ago, or maybe we did and just weren't aware of it!

 

[S J H]

Have you thought of a fan and duct, may be cheaper and easier

I think it might be, just have a fan hanging down in the middle of the building to blow the air to the end gable

 

[KK6610]

How about adding an outdoor yard to the lean to so cattle get some fresh air

 

[Sheep]

If the sides are sheeted then remove the bottom nails of every other sheet and stick a spacer in it (about 3" or more). So its like this |\ if you can see what I mean.

 

[Hesstondriver]

could you just remove a couple of roof sheets. it will make a real difference with convection taking the hot air out and will out weight any rain that comes in