Mushroom screws

[Dave Bebb]

Hi all have i leak on one of my mushroom vent i have stopped the leak for now but want to do a proper job in spring , The screws in now are cross heads in brass very tight and will snap i think when i try to unscrew .Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense . PS just thought i could go inside and pull the vent off and have a look but it would be nice to know the head size when i order new thanks Dave B

[bigste]

"Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense "

It does make a bit of sense but how on earth do you think anyone will know that, we aren't all telepathic. Mushrooms can vary from boat to boat.

[Guest]

Hi all have i leak on one of my mushroom vent i have stopped the leak for now but want to do a proper job in spring , The screws in now are cross heads in brass very tight and will snap i think when i try to unscrew .Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense . PS just thought i could go inside and pull the vent off and have a look but it would be nice to know the head size when i order new thanks Dave B

I think most people drill and tap the metalwork; I certainly did. Hard to say what yours will be. You should be able to measure the head of the screw with a small steel rule, and hopefully get an idea of the thread size from that.

Sounds like you may end up drilling them out

[by'eck]

Hi all have i leak on one of my mushroom vent i have stopped the leak for now but want to do a proper job in spring , The screws in now are cross heads in brass very tight and will snap i think when i try to unscrew .Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense . PS just thought i could go inside and pull the vent off and have a look but it would be nice to know the head size when i order new thanks Dave B

 

Almost certainly brass screws into tapped holes in the roof. Don't think self tapping brass screws would last long

[Jerra]

 

Almost certainly brass screws into tapped holes in the roof. Don't think self tapping brass screws would last long

I don't think brass is strong/hard enough to tap its own threads in metal.

[beerbeerbeerbeerbeer]

Remove the vent cover inside and have a feel around. My mushrooms are held down with screws and nuts. If yours are the same just keep any screws or bolts and hand them over the counter when buying new and they'll match them up.

You will of course need someone inside to grip the nut whilst you unscrew from above.

Seal with silicon when screwing back down.

[Guest]

"Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense "

It does make a bit of sense but how on earth do you think anyone will know that, we aren't all telepathic. Mushrooms can vary from boat to boat.

Strewth......five posts in and the OP gets a CWDF mauling.

[blackrose]

Many are 4mm brass but they are prone to snapping if you try to get them out. If so I would just drill them out and re-tap in 6mm and use stainless screws. If the vents are leaking take them off, clean up the roof and base of the vent and bed them in with Marineflex.

[mickp]

Mine were countersunk headed brass nuts bolts.i could grip the nut on the inside easily with the inner brass liner removed

[baldlimey]

And before you do anything make sure they are leaking and not just dripping from condensastion. You don't want to go to all that effort just to end up back where you started.

 

Guess how I know to check!

[Neil Smith]

Strewth......five posts in and the OP gets a CWDF mauling.

And that was post 2.

 

Neil

[dmr]

Think positive, get a good correctly fitting screwdriver (without any wear) and they may well come out. They are brass so will not have rusted, and they went in without breaking!

 

.............Dave

[blackrose]

Think positive, get a good correctly fitting screwdriver (without any wear) and they may well come out. They are brass so will not have rusted, and they went in without breaking!

 

.............Dave

 

Depends to some extent on whether the steel they've gone into has rusted, but yes they may come out.

[bizzard]

You can't beat brass screws with nuts inside, they'll almost always come out easily undamaged and to use again. With a little bit of fiddling inside I've never found it impossible to see to the nuts inside with a wee spanner or hold them still with small Mole grips.

[Guest]

And before you do anything make sure they are leaking and not just dripping from condensastion. You don't want to go to all that effort just to end up back where you started.

 

Guess how I know to check!

Very good point, ours drip with condensation, and also when raining very heavily it can bounce off the roof, in through the vent, and I get a few droplets of rain on my bald patch.

[Guest]

Very good point, ours drip with condensation, and also when raining very heavily it can bounce off the roof, in through the vent, and I get a few droplets of rain on my bald patch.

 

Ours did too. And annoyingly it was the one above the bed that was the worst. (jan's side though )

[Jess--]

Don't be afraid to give the screws a tap with a hammer (through a suitable screwdriver) to help with releasing them from the steel.

[Machpoint005]

You can't beat brass screws with nuts inside, they'll almost always come out easily undamaged and to use again. With a little bit of fiddling inside I've never found it impossible to see to the nuts inside with a wee spanner or hold them still with small Mole grips.

 

Heretic!

 

(No, I've used them too).

[Wanderer Vagabond]

Hi all have i leak on one of my mushroom vent i have stopped the leak for now but want to do a proper job in spring , The screws in now are cross heads in brass very tight and will snap i think when i try to unscrew .Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense . PS just thought i could go inside and pull the vent off and have a look but it would be nice to know the head size when i order new thanks Dave B

Out of curiosity how have you stopped the leak for now?

 

Having had a bit of a saga with my mushroom I would be loathe to take it off unless absolutely necessary. Mine had to come off since the centre rope had caught it and broke two of the screws so they had to be replaced to make it watertight again (for info they were brass and threaded into the roof). If however all of the screws seem to be intact I'd tend to get hold of something like 'Captain Tolleys Creeping Crack Cure' and put some around the base of the mushroom until it stops leaking. I used this on the chimney which started leaking (water, not fumes ) and it has worked a treat. It has made a pretty much 'invisible' repair and it hasn't leaked since I treated it, if it does in the future I'll just put some more CTCCC on it.

[WotEver]

I fixed a leaking vent in our conservatory roof at home with CTCCC - it took a few attempts cos it was a big vent and I didn't know where the leak was but it fixed it ?

[tillergirl]

We have just had the same problem. Our brass screws had snapped off and he had to drill the bits out then tap and die. He made a gasket out of some spare cusionfloor and used M4 16mm countersunk bolts not bothering with the nuts underneath. Until the weather is better and he can persuade the Marineflex to come out the tube hes used gutter sealant. The roof is getting a look at later this year so a proper fix on all of them is planned.

Edited January 27, 2016 by tillergirl

[Flyboy]

Hi all have i leak on one of my mushroom vent i have stopped the leak for now but want to do a proper job in spring , The screws in now are cross heads in brass very tight and will snap i think when i try to unscrew .Are they self tapping type or tapped and threaded and what is the counter sunk head size i will need to sit flush with the mushroom when screwed in if that makes sense . PS just thought i could go inside and pull the vent off and have a look but it would be nice to know the head size when i order new thanks Dave B

If your screws are brass they definitely won't be self tappers. Most mushroom vents are fixed with M5 csk bolts in tapped holes in the roof.

[Hardings Wood]

Is a CWDF mauling, a type of mushroom ?

[Wanderer Vagabond]

Is a CWDF mauling, a type of mushroom ?

Dunno, does it involve being kept in the dark and fed b*llsh*t??

[matty40s]

Dunno, does it involve being kept in the dark and fed b*llsh*t??

Tis if your batteries are gone and GrahameM is giving out advice..

 

There is no set standard for mushroom fixings, I have removed wood screws, M4, M5, 2bs, bolts with nuts etc etc.

As someone else says, a sharp bang with a hammer prior to removing the screw can help, if there's a nut inside it can be a pig.

Always mark which way the mushroom vent sits on the roof ( arrow to front or similar) so the holes line up when refitting.

If you have to redrill and tap to a larger size, remember to make the holes in the mushroom vent larger too.

We always use 3M tape to seal with a blob of acrylic sealant in the screw holes. Silicon is a bugger to remove completely and can lead to paint imperfections if you don't know it's there and fail to use fish eye additive or similar.

Edited January 27, 2016 by matty40s