Houdini hatch

[Johnny.kipps]

How do I minimise condensation on a Houdini hatch

[blackrose]

If it's double glazed the condensation should just be on the frame assuming there is no thermal break? However these things aren't absolute so even a double glazed unit with good thermal breaks in the frame could attract condensation on cold winter nights when it's nice and warm inside.

 

Personally I'd make a foam bung from a 2" thick sheet of medium density closed cell foam. You want it oversized so it seals the space at the perimeter, so if you're making it yourself cut it down to size gradually until you can wedge it in. You might need to screw a couple of small turnbuckles into the wooden surround to keep it in place at night. Then just remove it during the day.

 

Alternatively you could try a 3mm perspex or acrylic sheet held in place by self-adhesive strip magnets. There are some companies who cut the sheet to size for you. Make sure the sheet you're buying is UV tolerant otherwise it will yellow and craze quite quickly.

 

https://www.sodenplastics.co.uk/secondary-glazing-perspex

 

I've no idea what these people are like or if their products are good, just from a Google search.

Edited December 9, 2023 by blackrose

[Quattrodave]

6 hours ago, blackrose said:

Personally I'd make a foam bung from a 2" thick sheet of medium density closed cell foam. You want it oversized so it seals the space at the perimeter, so if you're making it yourself cut it down to size gradually until you can wedge it in. You might need to screw a couple of small turnbuckles into the wooden surround to keep it in place at night. Then just remove it during the day.

 

What Mr Blackrose said ^^

This is exactly what I did, although I only had 25mm (1") closed cell foam and it works perfectly...

[gatekrash]

We've got a piece of 3mm twinwall polycarbonate sheet (they sell them in sheets as replacement for greenhouse glass) cut to the size of the wooden frame. We attach it to the hatch with a small rubber sucker which has a string and a toggle attached (like the adjuster toggle on the bottom of a coat), the string is passed through a hole in the middle of the polycarbonate so that the sucker is one side and the toggle the other.

To fit it we just pull the string through the toggle to the max length, stick the sucker to the hatch then pull the string through the toggle to tighten the sheet up to the hatch.

Simple, and it stops nearly all the condensation. Without it we need a bucket under the thing !

 

[pearley]

7 hours ago, blackrose said:

Alternatively you could try a 3mm perspex or acrylic sheet held in place by self-adhesive strip magnets. There are some companies who cut the sheet to size for you. Make sure the sheet you're buying is UV tolerant otherwise it will yellow and craze quite quickly.

 

This is what we did. Works perfectly and can be left in place permanently until such time you want ventilation. 

Edited December 9, 2023 by pearley

[David6214]

Ours are held in with velcro tape (It was what I had at the time and its just kind of stayed). I tend to fit them around now and take them out in spring. We have a wooden screen that goes over.

 

We have Ethafoam bungs for the summer but more for the light than anything.

 

[cuthound]

Mine is secondary glazed with what looks like fluorescent tube diffuser. No drips at at 

 

 

[blackrose]

I don't have a Houdini hatch, but out of interest are they all just single glazed? Is that why the problem arises in the first place, or do you still get condensation on double glazed units?

[JoeC]

With my single glazed hatches I put cut down water tank lagging over the top, a sheet of waterproof material over the top and then use magnets to hold it all in place. Come the summer I take it all off.

This winter, my second on the boat, I have done the same but also used some stick on window film, which you heat to stretch it, over the hatch surround inside to give a bit of extra warmth - it also helped to stop the smaller bits of condensation that I got last winter.

[Peanut]

8 hours ago, blackrose said:

I don't have a Houdini hatch, but out of interest are they all just single glazed? Is that why the problem arises in the first place, or do you still get condensation on double glazed units?

Even if the hatch were double glazed, you may still get condensation on the frame which makes a cold bridge, so some condensation forms.

[SnippetySnip]

Thanks to the replies on this thread I figured out secondary glazing for my Houdini hatch which seems to work pretty well at preventing the condensation. The cold bridging effect on the Houdini frames is REAL!

 

I got 3mm Polycarbonate sheet cut to size from a supplier on the internet (not sure if I can name names or give links on the forum), and they also supply a self adhesive magnetic tape so the panel is easy to remove and doesn't look too tatty. 

[ditchcrawler]

16 minutes ago, SnippetySnip said:

  I got 3mm Polycarbonate sheet cut to size from a supplier on the internet (not sure if I can name names or give links on the forum),  

I don't see why not, it may be useful to others

[SnippetySnip]

I wasn't sure of the rules. But I used https://www.cutmy.co.uk

 

I'm sure this isn't the cheapest way to get polycarbonate, but from my perspective, it's worth a bit of extra spend to get a cleanly cut piece that is exactly the right size and shape. They are also selling the self adhesive magnetic tape.

 

Hope that helps someone.