[MassHistPres] Historic slate roof repair - tar

[Garrett Laws]

Sarah,

This is a very bad idea as it makes the situation worse. If there is
actually a leak originating at the seam between the slates, either the
slate below is broken and should be replaced (only the broken piece(s) need
to be replaced) or the slate below is shorter than it should be.
Additionally putting tar in the seam makes it nearly impossible to repair
once the real problem is discovered as there would then be a minimum of
three slates glued together making the only option to remove all tarred
slates.

The appropriate repair depends on a number of issues including the location
of the leak, transition of roof planes abutting the issue and frequently
the origination of the leak is far above where it shows up in the building
assembly.

Garrett Laws
Copper & Slate Co
Waltham

On Wednesday, November 1, 2023, Sarah White via MassHistPres <
masshistpres at cs.umb.edu> wrote:

> Good evening, MassHistPres -
>
> I am looking for information *from those with expertise in historic slate
> roofs*. We have an applicant who is proposing to "repair" portions of a
> slate roof with roof tar - directly applied to cracks in the slate. I have
> never seen this treatment advised from any standpoint. Please correct me if
> I am wrong.  The NPS guidance is not particularly helpful.
>
> Many thanks in advance.
>
> *Sarah White, MDS-HP*
> Senior Planner
> Planning, Preservation, & Zoning Division (PPZ)
>
> *Se habla espa**ñ**ol*
>
>
>
>
>
>
> *City of Somerville Public Records Notice*
>
> *Please be advised that the Massachusetts Attorney General has determined
> that email is a public record unless the content of the email falls within
> one of the stated exemptions under the Massachusetts Public Records Laws.*
>


-- 

Many Thanks,
Garrett Laws

The Copper & Slate Company <https://copperandslate.net>

Instagram <https://www.instagram.com/copperandslatecompany/>

The Copper & Slate Company, Inc.
Fine Roofing and Historic Carpentry
238 Calvary Street,
Waltham, MA 02453
(781) 893-1916

*LEAD FREE SINCE 2008*
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