# Seitz S4 window timber filler strip



## samsimillia (Jul 22, 2011)

Hi all
I am about to fit 4 Seitz S4 windows to my self build. I have a wall thickness of 52mm made up of 18mm GRP box, 25mm insulation and 9mm plywood. I understand I need to use a timber filler strip between the inner and outer frame but I can find no information on how to do this, what size or the best material to use. I read on this forum that someone used pvcU not timber. Any guidance would be most appreciated 
Thank you.


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## Pudsey_Bear (Sep 25, 2008)

samsimillia said:


> Hi all
> I am about to fit 4 Seitz S4 windows to my self build. I have a wall thickness of 52mm made up of 18mm GRP box, 25mm insulation and 9mm plywood. I understand I need to use a timber filler strip between the inner and outer frame but I can find no information on how to do this, what size or the best material to use. I read on this forum that someone used pvcU not timber. Any guidance would be most appreciated
> Thank you.


Hi and welcome to MHF.

It's a dependant on the length of screws you use, but there is a limit on how big a gap you can have, 50mm is about as big as I'd ever want to go, you have to consider the opening between the roll of blind material, and the outer frame, too big and youy lose small children and pets down the gap, I built on a panel van so only had a 1mm wall and about 20mm filler.

You'll need to remove the insulation where the two frame halves clamp together, the normal way is to fit the Seitz windows first, 10mm bead of black Sikaflex on the outer, to form a seal, a filler strip of treated timber (or UPVC) slaters lathe cut thickness, about 20mm x 30mm, 20mm being the filler dimension, 30mm giving you enough to clamp to and screw them together, leaving 10mm to fasten the ply to, you could go wider of course, screws should be 3.9mm thick for the Seitz frame, don't overtighten them, nearest I could find were plaster board screws, so I oiled them to help prevent rusting, I since found 3.9 in stainless, but I can't find the link right now, you could go 4mm http://www.ebay.co.uk/itm/4mm-8g-PA...TEEL-WOOD-SCREWS-FULLY-THREADED-/190732326744 and probably be okay

Have a look at these
http://forums.motorhomefacts.com/117-self-build/103999-pictures-my-self-build-last.html

https://www.dropbox.com/sh/yk0myzgzuz1m7n8/AAAOFzs51BoINp100lyH2KVWa?dl=0

Whilst it's nice to have another selfbuilder on here, there are other sites more dedicated to build, but not so good on the more social side of our hobby, MHF is the best side for advice once you're up and running.

http://sbmcc.co.uk/ free to register

http://www.diymotorhome.co.uk/ Free to register and use.

I am on both, as are a couple of MHF members.

Come back if I can help further, that's what this site is all about really.


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## samsimillia (Jul 22, 2011)

Hi and thanks 
We ended up painting some 3.6mm thick plywood black and using them cut to 31mm wide. Just got wood screws of the right length from screwfix as self tappers like they provide were not really necessary. When I wrote this message and first saw your reply I was away working and couldn't really visualize what it would look like and the comment of loosing small children and pets down there although I knew was a joke made me imagine this huge gap! Anyway the gap is insignificant and the black timber blends in with the window and is not really noticeable. So window 1 in, 3 more to go!
I choose this forum to post to as there was a thread from years ago talking about the same issue where the guy had uses uPVC so I posted here before trying elsewhere. I am aware of SBMCC but didn't know about DIY Motorhome so thanks for the heads upon that.
Our last 2 self builds are documented in the travellers section of my website POSITIVE EVOLUTION if you are interested.You have lots more detailed photos on yours though!
:wink2:


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## Pudsey_Bear (Sep 25, 2008)

Glad you got into and figured it out


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## Maria Graham Thirlwall (Aug 13, 2019)

Hi

Do you have any photos of your installation? We have the same issue with our walls being over 50mm thick. We are self building and have sonar Caravan Dometic windows.


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## samsimillia (Jul 22, 2011)

Maria Graham Thirlwall said:


> Hi
> 
> Do you have any photos of your installation? We have the same issue with our walls being over 50mm thick. We are self building and have sonar Caravan Dometic windows.


Not really, I have some pictures on my website of the build at https://samsimillia.wixsite.com/positive-evolution/my-third-conversion
I will see if I have any photos of the actual window fitting. In the end it was a lot simpler than I first imagined!


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## Pudsey_Bear (Sep 25, 2008)

the Seitz windows are of the clamshell type, not sure what type yours are so a picture would help.


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## samsimillia (Jul 22, 2011)

I don't have any detailed pictures of fitting the window. My build is on my website at https://samsimillia.wixsite.com/positive-evolution/my-third-conversion


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