How to stop a tin roof dripping

[ewald]

I have a workshop / store with a box profile roof, monopitch, which is almost unusable at this time of year due to condensation. Any ideas about lining/insulation to reduce the problem? I don't want to remove the sheets if possible, but would as a last resort. It is about 6m x 10m on wooden purlins.

 

[Lincs Lass]

Could you fasten kingspan under it

 

[phillipe]

Spray foam

 

[SilliamWhale]

Can you not put some air gaps in the wall?

 

[Dry Rot]

A cheap way is to fix plastic sheeting (builders' damp proof membrane) with timber lathes nailed throughto the purlins. That will stop the ondensation. I did this to a horse shelter at the suggestion of an architect and it worked fine.

 

[Lincsman]

What about foam backed plasterboard nailed/screwed on the underside of the purlins, pretty easy to do and would look really tidy.

 

[Steevo]

Simples. Nail some more bits of wood on top the roof running along the existing purlins, then put a second skin of tin on top. The air gap in the middle is your insulation and will stop the roof dripping.

 

[Paul E]

Fibre cement.

 

[Pennine Ploughing]

line it out on the underside of perlins with ply wood and paint it white, solve the driping make it warmer, and lighter for a workshop

 

[ewald]

Thanks - plenty of good ideas. How much difference will it make using some form of insulation, or will board or dpm be adequate?

 

[Exfarmer]

The reason for the condensation, is damp Air contacting the cold tin. Anything to prevent this happening will cure the problem. However just putting a second skin under the purlins will only work if it is insulated to stop that layer being cold.
Do be aware of ensuring that air passes freely over the purlins so they do not rot as they will if they stay damp from condensation
Ideally a layer of celotex or similar should cure the problem tacked on the bottom of the purlins.
You can be celotex rejects from a company in Wales

 

[Daddy Pig]

hang hessian between the purlins, this will absorb the moisture as it drips off the sheets and then it will evaporate

 

[Andrew1983]

Fibre cement.

We still get drips in fibre cement roofed buildings.

 

[Paul E]

That'll probably because you've got long sheets.
Where each sheet overlaps 1 purlin (5' 6") or so, it is very rare you get a drip in the shed.
But you could always ask them to leave!

 

[jamj]

Put breathable felt below, nailed unto purlins. Fix at ends with a piece of lath underneath.

 

[Sussex Martin]

Can you not put some air gaps in the wall?

I have an open fronted barn with Yorkshire boarding on two other sides and at times in winter it's like it's raining inside .

 

[Charolais cattle]

Hi i put Ballytherm insulation on my roof... measured the lengh of my box profile sheeting.. and Ballytherm cut insulation to length of sheeting.. got local lad to put it up.. he loosen the tex screws on 3 or 4 sheets at a time and slided the insulation down from top of sheet of clading. And refixed using longer tex screws.. and on skylights we jst put clear plastic and pulled it tight.. not a drip and we had snow today and not a drip to be seen.. I'll take few photo's of the job.. keeps heat in to...

 

[Hotbed]

Change it for 40mm composite roof sheets.