Joints opening up in my 4 panelled front door?

[michael]

My four panelled front door (exterior door) despite having been repaired and painted, constantly develops expansion/contraction cracks on its exterior face when the warm weather comes along.

I think the door is original (about 1880) and of pine construction and is approximately 2060mm (6’ 9”) high by 1040mm (3’ 5”) wide and 45mm (1 3/4”) thick. The four panels are about 30mm thick and are flat to the exterior face of the door and recessed to the internal face.

The construction is quite standard with a top, mid and bottom rail connecting to two side rails or stiles. Each of the four panels appear to be made up of two bits of timber as one can see the vertical joins in each panel i.e. twin panels in each of the four sections if you like.

The most severe cracks occur in the vertical joins between the panels and the side rails however there are also noticeable cracks in the twin panel joins mentioned above.

Contraction in the horizontal joins is minimal and the tennon joints between the rails are also quite secure. Interestingly these cracks only really appear on the outer face which is exposed to the weather. Any cracks on the inner face are quite miniscule.

Could somebody please advise on the best way to fix this problem as all my efforts with various fillers and coats of paint have failed

 

[MatthewC]

My guess is that the old casein glue on the tenons has become unglued (as it does) and you need to get the whole thing re-glued (if possible and if it's not rotten).

If you are anywhere near Buckingham/Oxford, I know an excellent joiner who could advise... He has just done my front door which is very similar in size and design to yours.

Matthew
http://houseintheenchantedforest.blogspot.com/

 

[michael]

Thanks Matthew
However as mentioned the ‘tennon’ joints which I presume only apply where the rails join one another, appear to be quite secure. What appears to be happening is contraction of the panels in warm weather which pull themselves away from the rails and only on the vertical joins. Is the panel/rail connection also a type of tennon joint?
I hate the idea of having to have the door taken away and repaired as I don’t have a replacement which suggests that I’ll have to board/padlock myself in or out of the house until the door is fixed and refitted.

 

[middi]

These exterior doors which were panelled and framed unless they were constantly kept in an excellent decorative state throughout their life they will eventually show signs of deteriorating and panel movement at their joints or in the frame casement groove.This is due to the fact that these panels, whilst originally glued at any of their individual planks that forms the panel, were never glued at the joint ( or groove) i the stiles or rails of the frame. This was ( and still is) to allow some movement of the expansion and contraction of the panels without any possibility of splitting or cracking of the mortice and tenons joints of the frame.
The fact that your door frame is still ok it means that the panels have done their job.
Unfortunately the same cannot be said for the condition of the panels, over the years these have suffered at their joints and exposed tongue that fits in the stiles grooves and they will always show signs of excessive movement no matter how well you paint them. In short the wood at the surface of the panel joints may have deteriorated. There is not an easy solution to this.
Dismantle door, check and repair/replace panels, or, prepair as best as you can and keep painting accepting the fact that it is a very old door that comes with some warts.

Middi

 

[Penners]

These exterior doors which were panelled and framed unless they were constantly kept in an excellent decorative state throughout their life they will eventually show signs of deteriorating and panel movement at their joints or in the frame casement groove.This is due to the fact that these panels, whilst originally glued at any of their individual planks that forms the panel, were never glued at the joint ( or groove) i the stiles or rails of the frame. This was ( and still is) to allow some movement of the expansion and contraction of the panels without any possibility of splitting or cracking of the mortice and tenons joints of the frame.

Middi's analysis is (of course) spot on. The crucial thing to remember is that wood expands and contracts almost entirely across the grain - very little along it. And the panels, being thinner than the stiles and rails, will expand and contract much more quickly as the relative humidity of the atmosphere changes.

If the door has not been constructed to allow for this sideways expansion/contraction of the panels, one (or both) of two effects will be seen:

1. If not enough "free" depth was left in the vertical grooves in the stiles to allow for panel expansion, the expanding panels can push the framing joints apart.

2. If the panels weren't made wide enough for plenty of their edges to be housed into the stile grooves, then when they contract their vertical edges can pull right out of the stiles. (This is, of course, an extreme case).

The panels should not be glued into the vertical grooves of the stiles. If they are, then contraction can cause the panels to crack. Ideally, in fact, they should only be glued into the rail grooves at a central spot, top and bottom. This allows them to expand and contract freely in their grooves. Of course, if generations of paint have effectively glued them all around, then you will tend to get constant cracking of the paint where it bridges the panel/stile housing. Or if, the paint is very thick and strong, it can even cause cracks in the panel.

As Middi said, the only truly effective solution is to dismantle the door and rebuild it correctly. But if there's a lot of paint packed into the panel housing grooves, you might (might) improve the situation by fully stripping the door and then repainting it. Do the painting in dry weather when the panels are as small as they're likely to get, and try to avoid allowing too much paint to pack into the panel housing grooves.

If you strip the paint chemically - don't use a dipping tank. Use something like Klingstrip.

 

[michael]

Thanks all

 

[CliffordPope]

On a wooden boat we would say that the problem is that the wood has dried out too much, and needs to be kept at a more constant humidity, ie by being in water rather than stored ashore.

So could the problem be that the panel has lost all its natural moisture, and is now excessively susceptable to changes in air temperature and humidity? Again from the nautical analogy, why not soak it in some natural oil, eg linseed, which would repel water and maintain a more even dimension?

 

[Lime]

On a wooden boat we would say that the problem is that the wood has dried out too much, and needs to be kept at a more constant humidity, ie by being in water rather than stored ashore.

So could the problem be that the panel has lost all its natural moisture, and is now excessively susceptable to changes in air temperature and humidity? Again from the nautical analogy, why not soak it in some natural oil, eg linseed, which would repel water and maintain a more even dimension?

I think that is the best solution.

 

[Penners]

why not soak it in some natural oil, eg linseed, which would repel water and maintain a more even dimension?

Oiling is a perfectly acceptable treatment, as is linseed oil paint, but neither will prevent movement of the wood.

 

[CliffordPope]

If the cause of the movement is alternate soaking and drying, surely picking a moment when the wood is bone dry and then saturating it in oil will at least inhibit re-absorption of moisture when the atmosphere turns damp?
I can see that the oil can't get through decades of paint, but starting from a stripped door?

 

[Penners]

Yes, the oil will "inhibit" transpiration, but it won't eliminate it - just slow it d0wn.

Oil is microporous.