Wet gable roofs

[Planetgood]

Hi I have increasingly bought gable roofs this year, and am massively disappointed to now find out how wet they are on the underside. Please is this a regular recognised problem?
I have new WBC roofs and National gable roofs, all have been carefully built with plenty of glue included. Granted they have been either ‘rock bottom’ or sale variety from a particular supplier, but in my view this makes them not fit for purpose? I assume the problem is that the sides of the galvanised metal is not long enough to extend past the wood of the upper panels of the roof so the wood wicks water in? I’ll try and attach a pic taken today of a damp underside of new wbc roof this year. Please has anyone solved this/any advice?
I do also have some Caddon Nat gable roofs new this year, made the same way, they are not damp. I need to visit the Caddon hive apiety again to check if the metal sides are longer on that brand maybe. Thank you for any insights!
(Not a very helpful pic. Yes lots of glue was put under the top central ridge piece of this roof when building it). Thanks

 

[JamezF]

What does the top of the roof look like?

James

 

[drex]

Have you got insulation above the crown board, and is the board closed off? Could be condensation

 

[Planetgood]

Have you got insulation above the crown board, and is the board closed off? Could be condensation

This hive is OMF, the feed holes are covered, no insulation on. There’s 1 or 2 more lifts on than currently needed for the brood&half stack inside. This pic isn’t particularly good example, others are soaking wet.
Other National hives do have insulation on and have the same problem, thank you

 

[Planetgood]

What does the top of the roof look like?

James

Looks normal, galvanised steel, pretty clean, glue visible at ends of the central wood strip

 

[pargyle]

This hive is OMF, the feed holes are covered, no insulation on. There’s 1 or 2 more lifts on than currently needed for the brood&half stack inside. This pic isn’t particularly good example, others are soaking wet.
Other National hives do have insulation on and have the same problem, thank you

I think it's condensation ... you would be amazed at how warm bees can keep the interior in winter ...I think what you are seeing is heat loss from the top of your hive that is causing moisture to condense on the cold surface of the inside of the roof. Presumably, if you are talking about lifts you have WBC 's ? With WBC's the top of the stack finishes with the crown board - the only roof is on the WBC. If this is your hive arrangement the very least I would do is add a slab of 50mm kingspan/celotex on top of the crown board. Indeed, I would almost be inclined to make a mini bonnet that has sides that drop down over the joint of the crownboard and the stack.

 

[Planetgood]

I think it's condensation ... you would be amazed at how warm bees can keep the interior in winter ...I think what you are seeing is heat loss from the top of your hive that is causing moisture to condense on the cold surface of the inside of the roof. Presumably, if you are talking about lifts you have WBC 's ? With WBC's the top of the stack finishes with the crown board - the only roof is on the WBC. If this is your hive arrangement the very least I would do is add a slab of 50mm kingspan/celotex on top of the crown board. Indeed, I would almost be inclined to make a mini bonnet that has sides that drop down over the joint of the crownboard and the stack.

Thank you, I don’t have this problem with any of my flat roof Nationals though, only with gable roofs Nationals and WBCs

 

[pargyle]

Thank you, I don’t have this problem with any of my flat roof Nationals though, only with gable roofs Nationals and WBCs

Because the heat from the crownboard is contained - so the underside of the flat roof is warmed a little and there is no large volume of moist air there to condense. WIth a gable roof you have space ... and air .. and warmth below and a cold surface above .... perfect conditions for condensation.

Have the gable roofs got those silly bee escape/ventilators on the gable as well ? If they have - Block them up ...

Insulation will solve the problem (and save the bees a lot of energy as well !)

 

[Newbeeneil]

When I assemble WBC roofs I put a bead of silicone mastic around the edge of the galvanised sheet as I've found, like you, that the water "wicks" into the ply and eventually delaminates it.
I have now taken to using cedar instead of ply as this is not as susceptible and was probably the wood used by W B Carr when he designed it.

 

[Newbeeneil]

I was taught when I started that if there was a dodgy joint or crack in the roof causing a leak to smear it with propolis. This works well for small leaks.

 

[pargyle]

When I assemble WBC roofs I put a bead of silicone mastic around the edge of the galvanised sheet as I've found, like you, that the water "wicks" into the ply and eventually delaminates it.
I have now taken to using cedar instead of ply as this is not as susceptible and was probably the wood used by W B Carr when he designed it.

Not only would it have been cedar - there would have been no covering of metal or anything else on top of the timber, I had a 50year old WBC in unpainted cedar - the roof was solid cedar, original to the hive and apart from a few ragged edges was perfectly serviceable - and totally rain proof.

 

[Planetgood]

Because the heat from the crownboard is contained - so the underside of the flat roof is warmed a little and there is no large volume of moist air there to condense. WIth a gable roof you have space ... and air .. and warmth below and a cold surface above .... perfect conditions for condensation.

Have the gable roofs got those silly bee escape/ventilators on the gable as well ? If they have - Block them up ...

Insulation will solve the problem (and save the bees a lot of energy as well !)

 

[Planetgood]

Really appreciate your reply thank you. I’ll go heavier with insulation generally. However will just post a couple pics taken now of colony that happens to be in garden - this Nat gable roof is on a small colony in single brood which has had 40mm insulation in situ as they’re abit small. Still damp thanks again!

 

[pargyle]

Really appreciate your reply thank you. I’ll go heavier with insulation generally. However will just post a couple pics taken now of colony that happens to be in garden - this Nat gable roof is on a small colony in single brood which has had 40mm insulation in situ as they’re abit small. Still damp thanks again!

Close up those escapes/ventilators and stick a couple of 25mm slabs of kingspan to the underside of the roof. That looks a bit like mildew - which will form in moist conditions.

 

[Newbeeneil]

Not only would it have been cedar - there would have been no covering of metal or anything else on top of the timber, I had a 50year old WBC in unpainted cedar - the roof was solid cedar, original to the hive and apart from a few ragged edges was perfectly serviceable - and totally rain proof.

In fact I have a very old WBC that I am yet to renovate which has cedar shingles on the roof.
Personally I would not be over worried about small patches of damp damp under a WBC roof as these will dry out with the amount of air that circulates within the outer skin.
The dampness under a gabled national roof is different as, although it has vents, there will be little air circulation if the hive is insulated and sealed well.
From Planetgoods pictures I would suggest he runs a bead of mastic around any joints between the galvanising and wood which should solve his problem.

 

[Planetgood]

In fact I have a very old WBC that I am yet to renovate which has cedar shingles on the roof.
Personally I would not be over worried about small patches of damp damp under a WBC roof as these will dry out with the amount of air that circulates within the outer skin.
The dampness under a gabled national roof is different as, although it has vents, there will be little air circulation if the hive is insulated and sealed well.
From Planetgoods pictures I would suggest he runs a bead of mastic around any joints between the galvanising and wood which should solve his problem.

Thanks will do this (but guess roofs have to be bone dry first). I had always struggled abit with the idea of making too well sealed because of the air circulation need.
I appreciate one pic looks like mildew, but other roofs are so heavy with water it’s worrying.
Think I’ll stick to flat roofs going forward!
Thanks

 

[JamezF]

I think my initial favoured explanation on the basis of what we've seen so far would be condensation on the underside of the cold roof, too. I'd not completely discount water wicking in from the edges of the ply though, as they don't appear to be very well protected by the metal wrapping around it. If you make any more of these I'd be tempted to seal the edges of the ply with something waterproof before assembling everything.

As the sides of the roof aren't that deep I'd try putting an eke on top of the crown board with 50mm of insulation inside and put the roof on top of that. I'd leave the roof ventilation open for the time being though, to try to help the roof to dry out. Once everything is dry it could be closed off.

I'd also check the underside of the ply on the outside of the roof to see if it is showing signs of damp. If it is that might suggest that at least some water is wicking in from the edges. Should that appear to be the case then drying the roof out completely and painting the underside of the ply where it's open to the elements with a sealant would perhaps be a good plan, but I'd still go with the insulation.

Overall though I have to say that the roof doesn't look the greatest design to me. I much prefer the metal covering on the roof to come down over the sides so the ply (or OSB) forming the top is completely covered. Neither do I like the screws in the top of the ridge piece that encourage water to puddle above them.

James

 

[JamezF]

Thanks will do this (but guess roofs have to be bone dry first). I had always struggled abit with the idea of making too well sealed because of the air circulation need.

When a colony in the hollow of a tree survives quite happily without an upper opening to allow air to circulate, is there a reason to believe that a colony in a hive should need one?

The idea that there's a need for air to circulate appears to have come about because condensation could form on the underside of the roof and (particularly) crownboard because there's warm air on the inside and they can be very cold on the outside. In theory, ventilation should help get rid of the condensation. In practice, it also helps the heat produced by the bees to keep themselves warm to escape. Insulating over the top of the brood chamber (which did used to be a relatively common practice as far as I can see, though it may have been a bag of wood shavings or straw at the time) means there isn't such cold air on the upper side of the crown board and so condensation is less likely to form underneath.

Condensation may still form on the walls, but there's a line of thought that suggests the bees may use that to dilute stored honey. I have no idea if that's true or not.

James

 

[Swarm]

If they are as saturated as you describe I'd agree with James that they are wicking at some point. I have a couple of flat roofs that are the same, they get very heavy, check around the nails as a suspect place for ingress.

 

[Ian123]

I hate gable roofs no place to stack anything, the 1 I do have the top batten fell off and at the very peak there’s an 8mm gap between metal sheets. I’d suspect water is getting under batten.