It's not easy being green - 1971 TC

[Dilkris]

Not that I doubt you - but why would Lotus want to waterproof the bulkhead?

[4129R]

Not that I doubt you - but why would Lotus want to waterproof the bulkhead?

Rainwater getting splashed up into the engine bay would get absorbed by the cardboard material used in the bulkhead.

Many Europas suffer from that cardboard crumbling as it is saturated. You have to remove the defective cardboard and replace with plywood and fibreglass over the plywood. Wet cardboard just falls apart.

[BDA]

I found this thread on the LotusEuropa group that might give you some ideas (https://groups.io/g/LotusEuropa/topic/71913211#msg161028).

[Kendo]

The original bulkhead, at least on my TCS was made from particle board., which is probably as absorbent as cardboard. As I understand it, its main function is to stiffen the body perpendicular to the fore/aft axis.

Since mine was decomposed, I replaced it with 1/2”? The right thickness of marine grade plywood. But others have used honeycomb aluminum and other extremely stiff, and fireproof, panels. Others still have added soundproofing to the cabin side. Ill probably add that when I do the interior in the next few months

[gideon]

The bulkhead serves all three purposes: structural, fire barrier and soundproofing.  The structural part is (I believe) low density fiberboard (LDF).  On the engine side is a layer of sound deadening felt with latex waterproofing, similar to this

https://www.woolies-trim.co.uk/p-1384-sound-deadening-felt

The sound deadening felt from Woolies is also fire retardant.  On the cabin side is a sheet of hardboard (aka beaverboard, masonite, etc.)  covered in carpet (but you all knew that).