Help identify my eaves make-up

14 Oct 2013
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United Kingdom
I'm doing a loft insulation project and looking at the eaves to ensure insulation and ventilation.

My ideal is to join ceiling insulation (cold loft) onto CWI, or near as possible.

However, to do this I have to find the CWI, and I'm coming up blank atm! The eaves are extremely difficult to reach especially with my short arms. Here are some piccies.

First, looking down into the eaves from the loft:

So there's a full height joist nearest the camera, then a half height joist, then some masonry where there's a birds mouth

Is that the soffit and fascia board? Why is that joist-like piece of timber cut off before reaching the wall there?

Note the CWI bead... I can't see where this is coming from!

Looking along the eaves, from the gable end. Note the timber running along the eaves, it starts from the first rafter in (see next image). Is that the outer leaf on the right? What about the masonry below that the timber is running along?

Detail of the end of the timber. I wondered if that extra piece of wood, that looks to be fitted vertically, might give some clues.

Inside of this, the plasterboard ceiling buts up against a piece of timber, where there's a gap I intend to fill. Here's looking at it from the top:

Here's looking at it from the bottom, and how it connects to the masonry:

To summarise:

- Where is the outer/inner leaf
- Do I have a wall plate?
- Why can't I see any CWI? Blocked by a the wall plate, if I have one?
- Do I need to take more piccies?
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All looks like a typical eaves detail.

I see the back side of the fascia and the back side of a timber soffit in one image. The timbers you see are cradling timbers put there to support the soffit.

The cavity is probably closed with masonry.

Bits of perished felt are visible too.

All typical.

Although there doesn't look like there is any soffit or fascia ventilation, you are unwise to cram up the eaves with insulation particularly if this is how the roof is being vented.
Thanks noseall. I certainly have no intention to block up the ventilation. I will be leaving a 25mm gap along the eaves using sheet insulation.

Is it possible to identify the outer leaf from these pictures? Are the cradling timbers sat on top of it?

When a cavity is closed by masonry is this by a lintel of some sort bridging both leaves or is something just stuffed into the cavity somehow?
There are a few different ways of constructing an eaves detail. In some instances the outer masonry continues up with the internal masonry and in others, the soffit actually rests on the external masonry.

Your images are a wee bit too close up to gain perspective. However, one image is showing what appears to be the head of a timber window or door. Seeing as there is no outer lintel above this, logic would suggest that your external leaf masonry finishes at soffit level. Your cavity must be closed or else the soffit void would be full of inso' beads.

It would be normal to carry on the cavity insulation above the soffit line so that it ties in with the loft insulation. However, eaves ventilators are installed in conjunction with this to prevent stifling the air flow. Just use your common sense.
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Yeah, sorry about the images. They are taken with the camera held at arms length with little clearance about, so it is quite difficult. It is not possible to access externally because there's a GF extension below which makes getting a ladder up difficult.

A timber window - of course! There is a window at that point. Why didn't I think of that?! I guess I didn't expect to see it mounted so high, essentially open to the roof space. Here the windows are mounted in the outer leaf, so that gives some pointers.

In the third picture you can see the timber plus what looks like another timber underneath the masonry on the right of the picture. Is the masonry the cavity closer, added like a lintel on top of the window/wall?

What I need to do next is check where I know the window *isn't*.

The CWI is retrofit btw - this part of the building is the original 50's build.

My plan is to see if I can wrap some thin loft roll down what-I-think-is-the-closer, ending where the timber window is. I will use EPS sheet between the rafters to hold the roll, both to add some insulatory effect and also to hold the roll to maintain the ventilation.

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